【LG5019】[NOIP2018]道路铺设

【LG5019】[NOIP2018]道路铺设

题面

洛谷

题解

(NOIP) 抄 (NOIP)差评

设当前做到了位置(i)

且(h_i) (-) (h_i)(_+)(_1) (=) (x)

若(x>0)将(x)加入贡献即可

#include<iostream>
#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<cmath>
#include<algorithm>
using namespace std;
inline int gi() {
	register int data = 0, w = 1;
	register char ch = 0;
	while (ch != '-' && !isdigit(ch)) ch = getchar();
	if (ch == '-') w = -1, ch = getchar();
	while (isdigit(ch)) data = data * 10 + ch - '0', ch = getchar();
	return w * data; 
}
#define MAX_N 100005 
int N, a[MAX_N], b[MAX_N];

int main () {
	N = gi();
	for (int i = 1; i <= N; i++) b[i] = a[i] = gi(); 
	for (int i = 1; i <= N; i++) b[i + 1] -= a[i];
	int ans = 0; 
	for (int i = 1; i <= N; i++) if (b[i] > 0) ans += b[i];
	printf("%d
", ans); 
	return 0; 
}