20分求助，悬关

Little_x_starTYJ @ 2023-09-11 17:29:53

#include <iostream>
using namespace std;
long long m[110][110][110];
long long w(int a, int b, int c) {
    if (a > 20 || b > 20 || c > 20)
        return w(20, 20, 20);
    if (m[a][b][c] != 0)
        return m[a][b][c];
    if (a <= 0 || b <= 0 || c <= 0)
        return m[a][b][c] = 1;
    else if (a > 20 || b > 20 || c > 20)
        return m[a][b][c] = w(20, 20, 20);
    else if (a < b and b < c)
        return m[a][b][c] = w(a, b, c - 1) + w(a, b - 1, c - 1) - w(a, b - 1, c);
    else
        return m[a][b][c] = w(a - 1, b, c) + w(a - 1, b - 1, c) + w(a - 1, b, c - 1) - w(a - 1, b - 1, c - 1);
}
int main() {
    while (1)
    {
        int a, b, c;
        scanf("%d%d%d", &a, &b, &c);
        if (a == -1 && b == -1 && c == -1)
            break;
        printf("w(%d, %d, %d) = %d\n", a, b, c, w(a, b, c));
    }
    return 0;
}

by Meteor_ @ 2023-09-11 18:12:10

你这个代码写的锅挺多

如果a,b,c中有小于0的，你得先判，否则负下标会RE

#include <iostream>
using namespace std;
long long m[110][110][110];
long long w(long long a, long long b, long long c) {
    if (a <= 0 || b <= 0 || c <= 0)
        return 1;
    if (m[a][b][c] != 0)
        return m[a][b][c];
    else if (a > 20 || b > 20 || c > 20)
        return m[a][b][c] = w(20, 20, 20);
    else if (a < b and b < c)
        return m[a][b][c] = w(a, b, c - 1) + w(a, b - 1, c - 1) - w(a, b - 1, c);
    else
        return m[a][b][c] = w(a - 1, b, c) + w(a - 1, b - 1, c) + w(a - 1, b, c - 1) - w(a - 1, b - 1, c - 1);
}
int main() {
    while (1)
    {
        long long a, b, c;
        scanf("%lld%lld%lld", &a, &b, &c);
        if (a == -1 && b == -1 && c == -1)
            break;
        printf("w(%lld, %lld, %lld) = ", a, b, c);
        if(a > 20)
            a = 21;
        if(b > 20)
            b = 21;
        if(c > 20)
            c = 21;
        printf("%lld\n", w(a, b, c));
    }
    return 0;
}

by Meteor_ @ 2023-09-11 18:12:27

@IOI_ILJYT

by int_stl @ 2023-09-24 21:49:04

#include <bits/stdc++.h>
using namespace std;
long long f[25][25][25];
long long w(long long a,long long b,long long c)
{
  if(a<=0||b<=0||c<=0) return 1;
  else if(a>20||b>20||c>20) return w(20,20,20);
  else if(f[a][b][c]!=0) return f[a][b][c];
  else if(a<b&&b<c) f[a][b][c]=w(a,b,c-1)+w(a,b-1,c-1)-w(a,b-1,c);
  else f[a][b][c]=w(a-1,b,c)+w(a-1,b-1,c)+w(a-1,b,c-1)-w(a-1,b-1,c-1);
  return f[a][b][c];
}
int main()
{
  long long a,b,c;
  while(cin>>a>>b>>c)
  {
    if(a==-1&&b==-1&&c==-1) break;
    cout<<"w("<<a<<", "<<b<<", "<<c<<") = "<<w(a,b,c)<<endl;
  }
  return 0;
}