力扣-74.搜索二维矩阵

题目链接

74.搜索二维矩阵

class Solution {
    public boolean searchMatrix(int[][] matrix, int target) {
        int m = matrix.length, n = matrix[0].length;
        int lowCol = 0, highCol = m - 1;
        while (lowCol <= highCol) {
            int midCol = (lowCol + highCol) / 2;
            if (matrix[midCol][0] < target) {
                lowCol = midCol + 1;
            } else if (matrix[midCol][0] > target) {
                highCol = midCol - 1;
            } else {
                return true;
            }
        }
        lowCol--;
        if (lowCol < 0)
            return false;
        int left = 0, right = n - 1;
        while (left <= right) {
            int mid = (left + right) / 2;
            if (matrix[lowCol][mid] < target) {
                left = mid + 1;
            } else if (matrix[lowCol][mid] > target) {
                right = mid - 1;
            } else {
                return true;
            }
        }
        return false;
    }
}

小结：依然是二分查找，注意边界值。