D - AtCoDeerくんと変なじゃんけんAtCoDeer and Rock-Paper

Problem Statement

AtCoDeer the deer and his friend TopCoDeer is playing a game. The game consists of NN turns. In each turn, each player plays one of the two gestures, Rockand Paper, as in Rock-paper-scissors, under the following condition:

(※) After each turn, (the number of times the player has played Paper)≦≦(the number of times the player has played Rock).

Each player's score is calculated by (the number of turns where the player wins) −− (the number of turns where the player loses), where the outcome of each turn is determined by the rules of Rock-paper-scissors.

(For those who are not familiar with Rock-paper-scissors: If one player plays Rock and the other plays Paper, the latter player will win and the former player will lose. If both players play the same gesture, the round is a tie and neither player will win nor lose.)

With his supernatural power, AtCoDeer was able to foresee the gesture that TopCoDeer will play in each of the NN turns, before the game starts. Plan AtCoDeer's gesture in each turn to maximize AtCoDeer's score.

The gesture that TopCoDeer will play in each turn is given by a string ss. If the ii-th (1≦i≦N)(1≦i≦N) character in ss is g, TopCoDeer will play Rock in the ii-th turn. Similarly, if the ii-th (1≦i≦N)(1≦i≦N) character of ss in p, TopCoDeer will play Paper in the ii-th turn.

Constraints

1≦N≦1051≦N≦105N=|s|N=|s|Each character in ss is g or p.The gestures represented by ss satisfy the condition (※).

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Input

The input is given from Standard Input in the following format:

ss

Output

Print the AtCoDeer's maximum possible score.

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Sample Input 1 Copy

Copy

gpg

Sample Output 1 Copy

Copy

0

Playing the same gesture as the opponent in each turn results in the score of 00, which is the maximum possible score.

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Sample Input 2 Copy

Copy

ggppgggpgg

Sample Output 2 Copy

Copy

2

For example, consider playing gestures in the following order: Rock, Paper, Rock, Paper, Rock, Rock, Paper, Paper, Rock, Paper. This strategy earns three victories and suffers one defeat, resulting in the score of 22, which is the maximum possible score.

题意：

你和对手进行石头布游戏，赢了的一分输了减一分。已知对手每次出什么（p-->布，g-->石头）同时还要保证进行到每一轮你出石头的总数大于等于你出布的总数。问你最多能的多少分。

思路：

模拟+贪心；

代码：  

#include<bits/stdc++.h> using namespace std; char s[100009]; int main() { int sg=0; int sp=0; int sum=0; scanf("%s",&s); int n=strlen(s); for(int i=0;i<n;i++) { if(sg==sp) { sg++; if(s[i]=='p') { sum--; } } else if(sg>sp) { if(s[i]=='g') { sp++; sum++; } else if(s[i]=='p') { sp++; } } } cout<<sum<<endl; }