#include <iostream>
#include <vector>
using namespace std;
int main() {
int n;
cin >> n;
vector<int> nums(n);
for (int i = 0; i < n; ++i) {
cin >> nums[i];
}
int maxReach = 0 ;
for (int i = 0; i < nums.size(); ++i) {
if (i > maxReach) {
cout<<"false"<<endl;
return 0;
}
maxReach = max(maxReach, i + nums[i]);
}
if(maxReach >= nums.size() - 1){
cout << "true" << endl;
}
else
cout << "false" << endl;
return 0;
}
if (i > maxReach) {
cout<<"false"<<endl;
return 0;
}
maxReach = max(maxReach, i + nums[i]);

京公网安备 11010502036488号