首页 > 技术文章 > lower_bound和upper_bound的实现

lakeone 2016-08-10 17:24 原文

int lowerBound(int* nums, int numsSize, int target) {
    //注意left和right的初始值必须是left = 0, right = numsSzie, 因为返回的位置可能是[0,numsSize]
    int left = 0;
    int right = numsSize;
    int mid;
    while (left < right)
    {
        mid = left + (right - left) / 2;
        if (nums[mid] >= target)
            right = mid;
        else
            left = mid + 1;
    }

    return left;
}

int upperBound(int* nums, int numsSize, int target) {
    int left = 0;
    int right = numsSize;
    int mid;
    while (left < right)
    {
        mid = left + (right - left) / 2;
        if (nums[mid] <= target)
            left = mid + 1;
        else
            right = mid;
    }
    return left;
}

  

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