[leetcode]Search a 2D matrix

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public class Solution { public boolean searchMatrix(int[][] matrix, int target) { if (matrix == null || matrix.length == 0) return false; int place = binarySearchColumn(matrix, target); if (place != matrix.length && matrix[place][0] == target) return true; if (place == 0) return false; int location = binarySearchRow(matrix[place-1], target); return location != matrix[place-1].length && matrix[place-1][location] == target; } private int binarySearchRow(int row[], int target){ int left = 0; int right = row.length-1; while (left <= right){ int mid = (left+right)/2; if (row[mid] > target){ right = mid-1; }else if (row[mid] < target){ left = mid+1; }else{ return mid; } } return left; } private int binarySearchColumn(int matrix[][], int target){ int left = 0; int right = matrix.length-1; while (left <= right){ int mid = (left+right)/2; if (matrix[mid][0] > target){ right = mid-1; }else if (matrix[mid][0] < target){ left = mid+1; }else{ return mid; } } return left; } }