12345678910111213141516171819202122232425bool check(int x) {/* ... */} // 检查x是否满足某种性质//两种整数二分方法// 区间[l, r]被划分成[l, mid]和[mid + 1, r]时使用:int bsearch_1(int l, int r){ while (l < r) { int mid = l + r >> 1; if (check(mid)) r = mid; // check()判断mid是否满足性质 else l = mid + 1; } return l;}// 区间[l, r]被划分成[l, mid - 1]和[mid, r]时使用:int bsearch_2(int l, int r){ while (l < r) { int mid = l + r + 1 >> 1; if (check(mid)) l = mid; else r = mid - 1; } return l;} 123456789101112131415//浮点数二分bool check(double x) {/* ... */} // 检查x是否满足某种性质double bsearch_3(double l, double r){ const double eps = 1e-6; // eps 表示精度,取决于题目对精度的要求 while (r - l > eps) { double mid = (l + r) / 2; if (check(mid)) r = mid; else l = mid; } return l;}