Leetcode 74 搜索二维矩阵

　　思路很明显，折半查找。

　　JAVA：

public final boolean searchMatrix(int[][] matrix, int target) {
        if (matrix.length == 0 || matrix[0].length == 0) {
            return false;
        }
        return search(matrix, target, 0);
    }

    private final boolean search(int[][] source, int target, int row) {
        if (row == source.length) {
            return false;
        }
        int len = source[row].length;
        if (source[row][len - 1] < target) {
            return search(source, target, row + 1);
        }
        int begin = 0;
        int end = len - 1;
        int mid = (begin + end) / 2;
        while (begin <= end) {
            if (begin == end || begin == end - 1) {
                if (source[row][begin] == target || source[row][end] == target) {
                    return true;
                }
                return false;
            }
            if (source[row][mid] == target) {
                return true;
            }
            if (source[row][mid] > target) {
                end = mid;
            } else {
                begin = mid;
            }
            mid = (begin + end) / 2;
        }
        return false;
    }

　　JS：

var searchMatrix = function (matrix, target) {
    if (matrix.length == 0 || matrix[0].length == 0) {
        return false;
    }
    return search(matrix, target, 0);
};

var search = function (arr, target, row) {
    if (row == arr.length) {
        return false;
    }
    if (arr[row][arr[0].length - 1] < target) {
        return search(arr, target, row + 1);
    }
    let begin = 0;
    let end = arr[row].length;
    let mid = Math.floor((begin + end) / 2);
    let currentRow = arr[row];
    while (begin <= end) {
        if (begin == end || begin == end - 1) {
            if (currentRow[begin] == target || currentRow[end] == target) {
                return true;
            }
            return false;
        }
        if (currentRow[mid] == target) {
            return true;
        }
        if (currentRow[mid] > target) {
            end = mid;
        } else {
            begin = mid;
        }
        mid = Math.floor((begin + end) / 2);
    }
}