C 解法, 执行用时: 2ms, 内存消耗: 332KB, 提交时间: 2020-07-26

#include <stdio.h>



int main()
{
  int x, y, n;
  scanf("%d %d %d", &x, &y, &n);
  int mm[31][31] = {0};
  int inputx, inputy;
  for(int i = 0; i < n; i++)
  {
    scanf("%d %d", &inputx, &inputy);
    mm[inputx][inputy] = 1;
  }
  long nn[31][31] = {0};
  nn[0][0] = 1;
   for(int i = 0; i <= x; i++)
   {
     for(int j = 0; j <= y; j++)
     {
       if(mm[i][j] == 1)
       {
         nn[i][j] = 0;
       }
       else
       {
         if(i >= 1)
           nn[i][j] += nn[i - 1][j];
         if(j >= 1)
           nn[i][j] += nn[i][j - 1];
       }
     }
   }
  printf("%ld\n", nn[x][y]);
  return 0;
}

C 解法, 执行用时: 2ms, 内存消耗: 360KB, 提交时间: 2020-05-12

int main(){
    int n,m,b;
    scanf("%d %d %d", &n, &m, &b);
    int i,j,k;
    int x,y;
    long long a[33][33] = {0};
 
    for (i=0;i<b;i++){
        scanf("%d %d", &x, &y);
        a[x][y] = -1;
    }
    if (a[0][0] == -1) printf("0");
    else {
        a[0][0] = 1;
        for (i=1;i<=n;i++){
            if (a[i][0] != -1) a[i][0] = a[i-1][0];
        }
        for (j=1;j<=m;j++){
            if (a[0][j] != -1) a[0][j] = a[0][j-1];
        }
        for (i=1; i<=n; i++)
            for (j=1; j<=m; j++) {
                if  (a[i][j] != -1) {
                    if (a[i-1][j] != -1) a[i][j] +=a[i-1][j];
                    if (a[i][j-1] != -1) a[i][j] +=a[i][j-1];
                }
            }
        if (a[n][m] != -1) printf("%lld", a[n][m]);
    }
    return 0;
}