数据结构上机习题3. 计算矩阵鞍点

#include <stdio.h>

void setupmatrix(int m, int n,int M[m][n]){
    int i,j;
    for(i=0;i<m;i++){
        for(j=0;j<n;j++){
            scanf("%d",&M[i][j]);
        }
    }
}
void printmatrix(int m,int n,int M[m][n]){
    int i,j;
    for(i=0;i<m;i++){
        for(j=0;j<n;j++){
            printf("%d ",M[i][j]);
        }
        printf("\n");
    }
}
int saddlepoint(int m,int n,int M[m][n]){
    int i,j,k;
    int row,col;
    for(i=0;i<m;i++){
        int min = M[i][0];
        for(j=0;j<n;j++){
            if(min>M[i][j]){
                min = M[i][j];
                col = j;
            }
        }
        int max = M[0][col];
        for(k=0;k<m;k++){
            if(max<M[k][col]){
                max = M[k][col];
                row = k;
            }
        }

        if(max == min){
            printf("the location is (%d,%d)\n",row,col);
            return max;
        }
    }
    return 0;
}
int main(){
    int m,n,num;
    printf("enetr m and n:");
    scanf("%d %d",&m,&n);

    int M[m][n];
    printf("enter a matrix:\n");

    setupmatrix(m,n,M);
    saddlepoint(m,n,M);

    printf("the saddle point is %d\n",saddlepoint(m,n,M));
    //printmatrix(m,n,M);

    return 0;
}

题目中的定义和鞍点的数学定义稍有不同，按照数学定义，应该是在矩阵中，一个数在所在行中是最大值，在所在列中是最小值，则被称为鞍点。

代码稍作改动则为

#include <stdio.h>

void setupmatrix(int m, int n,int M[m][n]){
    int i,j;
    for(i=0;i<m;i++){
        for(j=0;j<n;j++){
            scanf("%d",&M[i][j]);
        }
    }
}
void printmatrix(int m,int n,int M[m][n]){
    int i,j;
    for(i=0;i<m;i++){
        for(j=0;j<n;j++){
            printf("%d ",M[i][j]);
        }
        printf("\n");
    }
}
int saddlepoint(int m,int n,int M[m][n]){
    int i,j,k;
    int row,col;
    for(i=0;i<m;i++){
        int max = M[i][0];
        for(j=0;j<n;j++){
            if(max<M[i][j]){
                max = M[i][j];
                col = j;
            }
        }
        int min = M[0][col];
        for(k=0;k<m;k++){
            if(min>M[k][col]){
                min = M[k][col];
                row = k;
            }
        }

        if(max == min){
            printf("the location is (%d,%d)\n",row,col);
            return max;
        }
    }
    return 0;
}
int main(){
    int m,n,num;
    printf("enetr m and n:");
    scanf("%d %d",&m,&n);

    int M[m][n];
    printf("enter a matrix:\n");

    setupmatrix(m,n,M);
    saddlepoint(m,n,M);

    printf("the saddle point is %d\n",saddlepoint(m,n,M));
    //printmatrix(m,n,M);

    return 0;
}