题解 | 单组_二维数组

#include <stdio.h>
#include<stdlib.h>
int** arr(int m, int n) {
    int** arr = (int**)malloc(sizeof(int*)*m);
    for (int i = 0; i < m; i++) {
        arr[i] = (int*)malloc(n * sizeof(int));
        if (arr[i] == NULL) {

            for (int k = 0; k < i; k++) {
                free(arr[k]);
            }
            free(arr);

            return NULL;
        }
        for (int j = 0; j < n; j++) {
            scanf("%d", &arr[i][j]);
        }

    }
    return arr;
}
long long sum(int** arr, int m, int n) {
    long long sum = 0;
    for (int i = 0; i < m; i++) {
        for (int j = 0; j < n; j++) {
            sum += arr[i][j];
        }
    }
    return sum;
}

int main() {
    int m, n;
    long long  int ans;
    scanf("%d %d", &m, &n);
    int** arr1 = (int**)malloc(m * (sizeof(int*)));
    arr1 = arr( m, n);
    ans = sum(arr1,  m, n);
    printf("%lld", ans);
   
    for (int i=0; i<m; i++) {
        free(arr1[i]);
    }
    free(arr1);
    return 0;
}