题目描述
AtCoDeer the deer and his friend TopCoDeer is playing a game. The game consists of N turns. In each turn, each player plays one of the two gestures, Rock and 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 N 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 s. If the i-th (1≤i≤N) character in s is g, TopCoDeer will play Rock in the i-th turn. Similarly, if the i-th (1≤i≤N) character of s in p, TopCoDeer will play Paper in the i-th turn.
Constraints
1≤N≤10 5
N=|s|
Each character in s is g or p.
The gestures represented by s satisfy the 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 N 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 s. If the i-th (1≤i≤N) character in s is g, TopCoDeer will play Rock in the i-th turn. Similarly, if the i-th (1≤i≤N) character of s in p, TopCoDeer will play Paper in the i-th turn.
Constraints
1≤N≤10 5
N=|s|
Each character in s is g or p.
The gestures represented by s satisfy the condition (※).
输入
The input is given from Standard Input in the following format:
s
s
输出
Print the AtCoDeer's maximum possible score.
样例输入
gpg
样例输出
0
提示
Playing the same gesture as the opponent in each turn results in the score of 0, which is the maximum possible score.
来源
1 #include <iostream> 2 #include <bits/stdc++.h> 3 using namespace std; 4 string a; 5 int main() 6 { 7 cin>>a; 8 int ans=0; 9 int p=0; 10 for(int i=0;i<a.size();i++) 11 { 12 if(a[i]=='g') 13 { 14 if(p>0) 15 { 16 ans++; 17 p--; 18 } 19 else 20 { 21 p++; 22 } 23 } 24 else 25 { 26 if(p>0) 27 p--; 28 else 29 { 30 p++; 31 ans--; 32 } 33 34 } 35 } 36 cout << ans << endl; 37 return 0; 38 }