为何CE？

#include <bits/stdc++.h>
#include <windows.h>
using namespace std;

int n, p, d [ 5000005 ] = { 0 }, a, minn, x, y, z;

int main ()
{
	ios::sync_with_stdio ( false );
	cin.tie ( 0 );
	cin >> n >> p;
	for ( int i = 1; i <= n; i ++ )
	{
		cin >> d [ i ];
	}
	for ( int i = n; i > 1; i -- )
	{
		d [ i ] -= d [ i - 1 ];
	}
	while ( p -- )
	{
		cin >> x >> y >> z;
		d [ x ] += z;
		d [ y + 1 ] -= z;
	}
	minn = d [ 1 ];
	for ( int i = 2; i <= n; i ++ )
	{
		d [ i ] += d [ i - 1 ];
		if ( d [ i ] < minn )
		{
			minn = d [ i ];
		}
	}
	cout << minn << endl;
	return 0;
}