codeforces B#264. Caisa and Pylons

codeforces B#264. Caisa and Pylons

Caisa solved the problem with the sugar and now he is on the way back to home.

Caisa is playing a mobile game during his path. There are (n?+?1) pylons numbered from 0 to n in this game. The pylon with number 0 has zero height, the pylon with numberi (i?>?0) has heighth_i. The goal of the game is to reachn-th pylon, and the only move the player can do is to jump from the current pylon (let's denote its number ask) to the next one (its number will be k?+?1). When the player have made such a move, its energy increases byh_k?-?h_k?+?1 (if this value is negative the player loses energy). The player must have non-negative amount of energy at any moment of the time.

Initially Caisa stand at 0 pylon and has 0 energy. The game provides a special opportunity: one can pay a single dollar and increase the height of anyone pylon by one. Caisa may use that opportunity several times, but he doesn't want to spend too much money. What is the minimal amount of money he must paid to reach the goal of the game?

The first line contains integer n (1?≤?n?≤?10⁵). The next line containsn integers h₁,h₂,?..., h_n (1??≤??h_i??≤??10⁵) representing the heights of the pylons.

Print a single number representing the minimum number of dollars paid by Caisa.

5
3 4 3 2 4

4

3
4 4 4

4

In the first sample he can pay 4 dollars and increase the height of pylon with number0 by 4 units. Then he can safely pass to the last pylon.

題意：依次走過n+1個地方，每次從第i個走到第i+1個都會有hi-hi+1的能量，正的話，是加血，負的話是扣血，為了確保玩這個游戲，所以要保證血是正的，也可以通過花錢來增加高度來抵消血的損失，求最少的花費

思路：單純的模擬過去

#include 
#include 
#include 
#include 
typedef long long ll;
using namespace std;
const int maxn = 100005;

int arr[maxn];
int brr[maxn];

int main() {
	ll ans = 0;
	int n, a;
	scanf("%d", &n);
	int cnt = 0;
	for (int i = 1; i <= n; i++) {
		scanf("%d", &a);
		if (cnt < a) {
			ans += a - cnt;
			cnt = a;
		}
	}
	cout << ans << endl;
	return 0;
}