Loader,Plugin

矩阵四分：

class Solution {
public:
    bool searchMatrix(vector<vector<int>>& matrix, int target) {
        tar=target;
        return find(matrix,0,matrix.size()-1,0,matrix[0].size()-1);
    }
private:
    bool find(vector<vector<int>>& matrix,int row_left,int row_right,int col_top,int col_bottom){
        if(row_left>row_right||col_top>col_bottom||col_bottom>=matrix[0].size()||row_right>=matrix.size()) return false;
        if(row_left==row_right&&col_top==col_bottom&&tar!=matrix[row_left][col_bottom]) return false;
        int mid_row=(row_left+row_right)>>1;
        int mid_col=(col_top+col_bottom)>>1;
        if(tar==matrix[mid_row][mid_col]) return true;
        if(tar>matrix[mid_row][mid_col])
            return find(matrix,mid_row+1,row_right,col_top,mid_col)||
                    find(matrix,row_left,mid_row,mid_col+1,col_bottom)||
                    find(matrix,mid_row+1,row_right,mid_col+1,col_bottom);
        else return find(matrix,row_left,mid_row,col_top,mid_col)||
                    find(matrix,mid_row+1,row_right,col_top,mid_col)||
                    find(matrix,row_left,mid_row,mid_col+1,col_bottom);
    }
private:
    int tar;
};

Z字形查找：

Krahets - 力扣（LeetCode）：

class Solution {
public:
    bool searchMatrix(vector<vector<int>>& matrix, int target) {
        int m=0,n=matrix[0].size()-1;
        while(m<matrix.size()&&n>=0&&matrix[m][n]!=target){
            if(matrix[m][n]>target) --n;
            else ++m;
        }
        cout<<m<<' '<<n;
        if(m<matrix.size()&&n>=0) return true;
        return false;
    }
};

暴力解法：

class Solution {
public:
    bool searchMatrix(vector<vector<int>>& matrix, int target) {
        for(int i=0;i<matrix.size();++i)
            for(int &num:matrix[i])
                if(num==target) return true;
        return false;
    }
};