1 | // Copyright (c) 2000 David Abrahams. |
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2 | // Distributed under the Boost Software License, Version 1.0. |
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3 | // (See accompanying file LICENSE_1_0.txt or copy at |
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4 | // http://www.boost.org/LICENSE_1_0.txt) |
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5 | // |
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6 | // Copyright (c) 1994 |
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7 | // Hewlett-Packard Company |
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8 | // |
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9 | // Permission to use, copy, modify, distribute and sell this software |
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10 | // and its documentation for any purpose is hereby granted without fee, |
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11 | // provided that the above copyright notice appear in all copies and |
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12 | // that both that copyright notice and this permission notice appear |
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13 | // in supporting documentation. Hewlett-Packard Company makes no |
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14 | // representations about the suitability of this software for any |
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15 | // purpose. It is provided "as is" without express or implied warranty. |
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16 | // |
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17 | // Copyright (c) 1996 |
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18 | // Silicon Graphics Computer Systems, Inc. |
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19 | // |
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20 | // Permission to use, copy, modify, distribute and sell this software |
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21 | // and its documentation for any purpose is hereby granted without fee, |
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22 | // provided that the above copyright notice appear in all copies and |
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23 | // that both that copyright notice and this permission notice appear |
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24 | // in supporting documentation. Silicon Graphics makes no |
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25 | // representations about the suitability of this software for any |
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26 | // purpose. It is provided "as is" without express or implied warranty. |
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27 | // |
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28 | #ifndef BINARY_SEARCH_DWA_122600_H_ |
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29 | # define BINARY_SEARCH_DWA_122600_H_ |
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30 | |
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31 | # include <boost/detail/iterator.hpp> |
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32 | # include <utility> |
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33 | |
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34 | namespace boost { namespace detail { |
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35 | |
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36 | template <class ForwardIter, class Tp> |
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37 | ForwardIter lower_bound(ForwardIter first, ForwardIter last, |
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38 | const Tp& val) |
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39 | { |
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40 | typedef detail::iterator_traits<ForwardIter> traits; |
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41 | |
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42 | typename traits::difference_type len = boost::detail::distance(first, last); |
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43 | typename traits::difference_type half; |
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44 | ForwardIter middle; |
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45 | |
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46 | while (len > 0) { |
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47 | half = len >> 1; |
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48 | middle = first; |
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49 | std::advance(middle, half); |
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50 | if (*middle < val) { |
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51 | first = middle; |
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52 | ++first; |
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53 | len = len - half - 1; |
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54 | } |
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55 | else |
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56 | len = half; |
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57 | } |
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58 | return first; |
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59 | } |
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60 | |
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61 | template <class ForwardIter, class Tp, class Compare> |
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62 | ForwardIter lower_bound(ForwardIter first, ForwardIter last, |
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63 | const Tp& val, Compare comp) |
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64 | { |
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65 | typedef detail::iterator_traits<ForwardIter> traits; |
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66 | |
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67 | typename traits::difference_type len = boost::detail::distance(first, last); |
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68 | typename traits::difference_type half; |
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69 | ForwardIter middle; |
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70 | |
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71 | while (len > 0) { |
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72 | half = len >> 1; |
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73 | middle = first; |
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74 | std::advance(middle, half); |
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75 | if (comp(*middle, val)) { |
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76 | first = middle; |
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77 | ++first; |
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78 | len = len - half - 1; |
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79 | } |
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80 | else |
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81 | len = half; |
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82 | } |
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83 | return first; |
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84 | } |
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85 | |
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86 | template <class ForwardIter, class Tp> |
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87 | ForwardIter upper_bound(ForwardIter first, ForwardIter last, |
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88 | const Tp& val) |
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89 | { |
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90 | typedef detail::iterator_traits<ForwardIter> traits; |
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91 | |
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92 | typename traits::difference_type len = boost::detail::distance(first, last); |
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93 | typename traits::difference_type half; |
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94 | ForwardIter middle; |
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95 | |
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96 | while (len > 0) { |
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97 | half = len >> 1; |
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98 | middle = first; |
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99 | std::advance(middle, half); |
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100 | if (val < *middle) |
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101 | len = half; |
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102 | else { |
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103 | first = middle; |
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104 | ++first; |
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105 | len = len - half - 1; |
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106 | } |
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107 | } |
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108 | return first; |
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109 | } |
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110 | |
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111 | template <class ForwardIter, class Tp, class Compare> |
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112 | ForwardIter upper_bound(ForwardIter first, ForwardIter last, |
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113 | const Tp& val, Compare comp) |
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114 | { |
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115 | typedef detail::iterator_traits<ForwardIter> traits; |
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116 | |
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117 | typename traits::difference_type len = boost::detail::distance(first, last); |
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118 | typename traits::difference_type half; |
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119 | ForwardIter middle; |
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120 | |
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121 | while (len > 0) { |
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122 | half = len >> 1; |
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123 | middle = first; |
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124 | std::advance(middle, half); |
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125 | if (comp(val, *middle)) |
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126 | len = half; |
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127 | else { |
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128 | first = middle; |
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129 | ++first; |
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130 | len = len - half - 1; |
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131 | } |
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132 | } |
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133 | return first; |
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134 | } |
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135 | |
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136 | template <class ForwardIter, class Tp> |
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137 | std::pair<ForwardIter, ForwardIter> |
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138 | equal_range(ForwardIter first, ForwardIter last, const Tp& val) |
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139 | { |
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140 | typedef detail::iterator_traits<ForwardIter> traits; |
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141 | |
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142 | typename traits::difference_type len = boost::detail::distance(first, last); |
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143 | typename traits::difference_type half; |
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144 | ForwardIter middle, left, right; |
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145 | |
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146 | while (len > 0) { |
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147 | half = len >> 1; |
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148 | middle = first; |
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149 | std::advance(middle, half); |
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150 | if (*middle < val) { |
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151 | first = middle; |
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152 | ++first; |
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153 | len = len - half - 1; |
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154 | } |
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155 | else if (val < *middle) |
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156 | len = half; |
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157 | else { |
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158 | left = boost::detail::lower_bound(first, middle, val); |
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159 | std::advance(first, len); |
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160 | right = boost::detail::upper_bound(++middle, first, val); |
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161 | return std::pair<ForwardIter, ForwardIter>(left, right); |
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162 | } |
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163 | } |
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164 | return std::pair<ForwardIter, ForwardIter>(first, first); |
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165 | } |
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166 | |
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167 | template <class ForwardIter, class Tp, class Compare> |
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168 | std::pair<ForwardIter, ForwardIter> |
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169 | equal_range(ForwardIter first, ForwardIter last, const Tp& val, |
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170 | Compare comp) |
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171 | { |
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172 | typedef detail::iterator_traits<ForwardIter> traits; |
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173 | |
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174 | typename traits::difference_type len = boost::detail::distance(first, last); |
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175 | typename traits::difference_type half; |
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176 | ForwardIter middle, left, right; |
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177 | |
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178 | while (len > 0) { |
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179 | half = len >> 1; |
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180 | middle = first; |
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181 | std::advance(middle, half); |
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182 | if (comp(*middle, val)) { |
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183 | first = middle; |
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184 | ++first; |
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185 | len = len - half - 1; |
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186 | } |
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187 | else if (comp(val, *middle)) |
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188 | len = half; |
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189 | else { |
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190 | left = boost::detail::lower_bound(first, middle, val, comp); |
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191 | std::advance(first, len); |
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192 | right = boost::detail::upper_bound(++middle, first, val, comp); |
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193 | return std::pair<ForwardIter, ForwardIter>(left, right); |
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194 | } |
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195 | } |
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196 | return std::pair<ForwardIter, ForwardIter>(first, first); |
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197 | } |
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198 | |
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199 | template <class ForwardIter, class Tp> |
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200 | bool binary_search(ForwardIter first, ForwardIter last, |
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201 | const Tp& val) { |
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202 | ForwardIter i = boost::detail::lower_bound(first, last, val); |
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203 | return i != last && !(val < *i); |
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204 | } |
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205 | |
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206 | template <class ForwardIter, class Tp, class Compare> |
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207 | bool binary_search(ForwardIter first, ForwardIter last, |
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208 | const Tp& val, |
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209 | Compare comp) { |
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210 | ForwardIter i = boost::detail::lower_bound(first, last, val, comp); |
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211 | return i != last && !comp(val, *i); |
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212 | } |
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213 | |
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214 | }} // namespace boost::detail |
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215 | |
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216 | #endif // BINARY_SEARCH_DWA_122600_H_ |
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