Leetcode 74. 搜索二维矩阵

题目

Leetcode 74. 搜索二维矩阵

代码（首刷自解）

class Solution {
public:
    bool searchMatrix(vector<vector<int>>& matrix, int target) {
        int m = matrix.size(), n = matrix[0].size();
        int count = m*n-1;
        int low = 0, high = count;
        while(low <= high) {
            int mid = (high-low)/2+low;
            int x = mid/n, y = mid % n;
            if(matrix[x][y] > target) {
                high = mid-1;
            } else if(matrix[x][y] < target) {
                low = mid+1;
            } else {
                return true;
            }
        }
        return false;
    }
};

代码（8.11 二刷自解）

func searchMatrix(matrix [][]int, target int) bool {
    m, n := len(matrix), len(matrix[0])
    left, down := 0, m-1
    for left < n && down >= 0 {
        if matrix[down][left] < target {
            left++
        } else if matrix[down][left] > target {
            down--
        } else {
            return true
        }
    }
    return false
}

代码（9.18 三刷自解）

class Solution {
public:
    bool searchMatrix(vector<vector<int>>& matrix, int target) {
        int m = matrix.size(), n = matrix[0].size();
        int left = 0, right = m*n-1;
        while(left <= right) {
            int mid = (left+right)/2;
            int x = mid/n, y = mid%n;
            if(matrix[x][y] < target) {
                left = mid + 1;
            } else if(matrix[x][y] > target) {
                right = mid - 1;
            } else {
                return true;
            }
        }
        return false;
    }
};