神马意思？

#include<bits/stdc++.h>
using namespace std;
vector<int>code;
struct point{
	int l,r;
};
vector<point>chaozuo;
string decode(vector<int>code,vector<point>cz){
	string ret;
	for(int i=1;i<=(int)cz.size();i++){
		int l=cz[i].l,r=cz[i].r;
		string t;
		t.resize(r-l+1);
		t[0]=0;
		for(int j=l;j<r;j++){
			t[j]=t[j-1]+code[j];
			
		}
		for(int i=1;i<=r-l+1;i++) ret+=t[i];
	}
	return ret;
}
int main(){
	int n,m;
	scanf("%d%d",&n,&m);
	for(int i=1;i<=n;i++){
		int t;
		scanf("%d",&t);
		code.push_back(t);
	}
	for(int i=1;i<=m;i++){
		int l,r;
		scanf("%d%d",&l,&r);
		chaozuo.push_back({l,r});
	}
	cout<<decode(code,chaozuo);
	return 0;
}

2 1
60 5
0 1

terminate called after throwing an instance of 'std::length_error'
  what():  basic_string::_M_replace_aux
return 3;