题干：
链接：https://ac.nowcoder.com/acm/contest/888/G
来源：牛客网
Gromah and LZR have entered the seventh level. There are a sequence of gemstones on the wall.
After some tries, Gromah discovers that one can take exactly three successive gemstones with the same types away from the gemstone sequence each time, after taking away three gemstones, the left two parts of origin sequence will be merged to one sequence in origin order automatically.
For example, as for "ATCCCTTG", we can take three 'C's away with two parts "AT", "TTG" left, then the two parts will be merged to "ATTTG", and we can take three 'T's next time.
The password of this level is the maximum possible times to take gemstones from origin sequence.
Please help them to determine the maximum times.
输入描述:
Only one line containing a string ss_{}s, denoting the gemstone sequence, where the same letters are regarded as the same types.
1≤∣s∣≤1051 \le |s| \le 10^51≤∣s∣≤105
ss_{}s only contains uppercase letters.
输出描述:
Print a non-negative integer in a single line, denoting the maximum times.示例1
输入
复制
ATCCCTTG输出
复制
2说明
One possible way is that ‘‘ATCCCTTG " → ‘‘ATTTG " →‘‘AG "``ATCCCTTG\," \; \rightarrow \; ``ATTTG\," \; \rightarrow ``AG\,"‘‘ATCCCTTG"→‘‘ATTTG"→‘‘AG".题目大意：
给一个字符串 3个连续且相同的能够消去 问这个字符串最多消去几次
解题报告：
栈模拟。
AC代码：
#include<cstdio>
#include<iostream>
#include<algorithm>
#include<queue>
#include<map>
#include<vector>
#include<set>
#include<string>
#include<cmath>
#include<cstring>
#define FF first
#define SS second
#define ll long long
#define pb push_back
#define pm make_pair
using namespace std;
typedef pair<int,int> PII;
const int MAX = 2e5 + 5;
char s[MAX];
char stk[MAX];
int top = 100,ans;
int ok() {if(stk[top] == stk[top-1] && stk[top-1] == stk[top-2]) {top -= 3;return 1;}else return 0;
}
int main()
{cin>>s+1;int len = strlen(s+1);for(int i = 1; i<=len; i++) {stk[++top] = s[i];ans += ok();}printf("%d\n",ans);return 0 ;
}
