No.272 - LeetCode[861] Score After Flipping Matrix - 贪心

贪心

/*
 * @lc app=leetcode id=861 lang=cpp
 *
 * [861] Score After Flipping Matrix
 */

// @lc code=start
class Solution {
public:
    int calculate(vector<vector<int>>& grid) {
        int N = grid.size();
        int M = grid[0].size();
        int ans = 0;

        for(int i=0;i<N;i++){
            int row = 0;
            for(int j=0;j<M;j++){
                row <<= 1;
                row += grid[i][j];
            }
            ans += row;
        }
        return ans;
    }
    bool transRow(vector<vector<int>>& grid) {
        int N = grid.size();
        int M = grid[0].size();
        bool ans = false;

        for(int i=0;i<N;i++){
            int a = 0,b = 0;
            for(int j=0;j<M;j++){
                a += grid[i][j];
                b += (grid[i][j] == 0 ? 1 : 0 );
                a <<= 1;
                b <<= 1;
            }
            if(b > a){
                for(int j=0;j<M;j++){
                    grid[i][j] = (grid[i][j] == 0 ? 1 : 0 );
                }
                ans = true;
            }
        }
        return ans;
    }
    bool transColumn(vector<vector<int>>& grid) {
        int N = grid.size();
        int M = grid[0].size();

        bool ans = false;

        for(int j=0;j<M;j++){
            int cnt = 0;
            for(int i=0;i<N;i++){
                cnt += (grid[i][j] == 0 ? 1 : 0 );
            }
            if(cnt > N/2){
                for(int i=0;i<N;i++){
                    grid[i][j] = (grid[i][j] == 0 ? 1 : 0 );
                }
                ans = true;
            }
        }
        return ans;
    }
    int matrixScore(vector<vector<int>>& grid) {
        bool flagRow, flagColumn;
        do {
            flagRow = transRow(grid);
            //print(grid);
            flagColumn = transColumn(grid);
            //print(grid);
        }while(flagRow || flagColumn) ;
        return calculate(grid);
    }
};
// @lc code=end