感觉没什么问题了，为什么全红？救救孩子吧

#include<bits/stdc++.h>
using namespace std;
long long a,b,c;
long long r[25][25][25] = {};
long long w(long long i,long long j,long long k){
    if (i <= 0 || j <= 0 || k <= 0)  return 1;
    if(i>20||j>20||k>20)  return w(20,20,20);
    else if(i<j&&j<k){
        if(r[i][j][k-1] == 0)  r[i][j][k-1] = w(i,j,k-1);
        if(r[i][j-1][k-1] == 0)  r[i][j-1][k-1] = w(i,j-1,k-1);
        if(r[i][j-1][k] == 0)  r[i][j-1][k] = w(i,j-1,k);
        return r[i][j][k-1]+r[i][j-1][k-1]-r[i][j-1][k];
    }else{
        if(r[i-1][j][k] == 0)  r[i-1][j][k] = w(i-1,j,k);
        if(r[i-1][j-1][k] == 0)  r[i-1][j-1][k] = w(i-1,j-1,k);
        if(r[i-1][j][k-1] == 0)  r[i-1][j][k-1] = w(i-1,j,k-1);
        if(r[i-1][j-1][k-1] == 0)  r[i-1][j-1][k-1] = w(i-1,j-1,k-1);
        return r[i-1][j][k]+r[i-1][j-1][k]+r[i-1][j][k-1]-r[i-1][j-1][k-1];
    }
}//w(1, 1, 1) = 2
//w(2, 2, 2) = 4
int main(){
    cin>>a>>b>>c;
    while (!(a==-1&&b==-1&&c==-1)){
        if (a>20) a = 20;
        if (b>20) b = 20;
        if (c>20) c = 20;
        cout<<"w("<<a<<", "<<b<<", "<<c<<") = "<<w(a,b,c)<<endl;
        cin>>a>>b>>c;
    }
    return 0;
}

用了个不那么彻底的记忆化搜索和递归，r用来储存记忆化搜索，结果吗。。。自己看

（十分感谢大佬的指教）