题目：

代码：

public static boolean searchMatrix(int[][] matrix, int target) {int rows = matrix.length;int columns = matrix[0].length;// 先找到行，行为当前行第一列<target，当前行+1行，第一列>targetfor (int i = 0; i < rows; i++) {if (matrix[i][0] == target) {return true;} else if (i + 1 == rows || matrix[i + 1][0] > target && matrix[i][0] < target) {   // 这里从下标0开始，遍历到最后一行数组下标越界问题耗费了很长时间，注：最后一行 i+1==rows直接进行二分int left = 0, right = columns - 1;while (left <= right) {int mid = left + (right - left) / 2;if (matrix[i][mid] == target) {return true;} else if (matrix[i][mid] > target) {right = mid - 1;} else {left = mid + 1;}}} else {// continue;}}return false;
}