1.5.1 Number Triangles

/*
ID: awsd1231
PROG: numtri
LANG: C++
*/
#include<iostream>
#include<cstdio>
using namespace std;
int a[1001], b[1001];
int* x = a, *y = b, *t;
int n;
int ans(int* x, int n) {
	int maxAns = x[0];
	for(int i = 0; i != n; ++i) {
		if(x[i] > maxAns) maxAns = x[i];
	}
	return maxAns;
}
int main() {
	freopen("numtri.in", "r", stdin);
	freopen("numtri.out", "w", stdout);
	cin >> n;
	cin >> x[0];
	for(int i = 1; i != n; ++i) {
		for(int j = 0; j != i + 1; ++j) {
			cin >> y[j];
			if(!j) y[j] = y[j] + x[j];
			else y[j] += max(x[j], x[j-1]);
		} 
		t = x; x = y; y = t;
	}
	cout << ans(x, n) << endl;
	return 0;
}