大神们帮忙找找问题~

#include<bits/stdc++.h>
using namespace std;
int main(){
	int a,n,m,x;
	cin>>a>>n>>m>>x;
	int sum1[25],sum2[25],i,ans[25];
	sum1[1]=1;sum1[2]=0;sum2[1]=0;sum2[2]=1;ans[1]=a;ans[2]=a;
	for(i=3;i<=n-1;i++){
		sum1[i]=sum1[i-1]+sum1[i-2];
		sum2[i]=sum2[i-1]+sum2[i-2];
	}
	int t=(m-sum1[n-1]*a)/sum2[n-1];
	for(i=3;i<=n-1;i++) ans[i]=ans[i-1]+sum1[i]*a+sum2[i]*t-sum1[i-1]*a-sum2[i-1]*t;
	ans[n]=ans[n-1];
	cout<<ans[x];
	return 0;
}

谢谢！