编译失败

#include<bits/stdc++.h>
using namespace std;
void msort(int s,int t){
	if(s==t) return;
	int mid=(s+t)/2;
	msort(s,mid);
	msort(mid+1,t);
	int i=s,j=mid+1,k=s;
	while((i<mid) && (j<=t)){
		ifa[i]<=a[j]){
			r[k]=a[i];k++;i++;
		}else
		r[k]=a[j];k++;j++;
		ans+=mid-i+1;
	}
	while(i<=mid){
		r[k]=a[i];k++;j++;
	}
	for(int i=s;i<=t;i++)
}