POJ 1690

一道水题，不过很多细节没注意结果拖了很久还一直WA，总之用堆来记录括号，整体上还是比较简单的，但是细节一定要想清楚。

#include <iostream>
#include <algorithm>
#include <queue>
#include <string>
#include <vector>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cassert>
#include <cmath>
#include <string>
#include <stack>
#include <map>
#include <set>
#include <deque>
using namespace std;

const int maxl= (1<<8)+5;

struct Node
{
	int sg;
	char op;
	int pos;
	Node(int ssg= 0, char oop= 0, int ppos= 0) : sg(ssg), op(oop), pos(ppos) {}
};
char sen[maxl];
bool drop[maxl];
stack<Node> S;

char SearchBack(int x)
{
	for (int i= x-1; i>= 0; --i){
		if (' '!= sen[i]){
			return sen[i];
		}
	}

	return '^';
}

int main(int argc, char const *argv[])
{
	int kase= 0;
	scanf("%d ", &kase);

	while (kase--){
		while (!S.empty()){
			S.pop();
		}
		memset(drop, 0, sizeof(drop));
		fgets(sen, maxl, stdin);
		int lth= strlen(sen);
		Node t;

		for (int i= 0; i< lth; ++i){
			if (' '== sen[i]){
				drop[i]= 1;
			}
			else if ('('== sen[i]){
				S.push(Node(1, SearchBack(i), i));
			}
			else if ('+'== sen[i] || '-'== sen[i]){
				if (!S.empty()){
					S.top().sg= 0;
				}
			}
			else if (')'== sen[i]){
				t= S.top();
				if ('-'!= t.op || t.sg){
					drop[t.pos]= drop[i]= 1;
				}
				S.pop();
				if (!S.empty()){
					S.top().sg &= t.sg;
				}
			}
		}

		for (int i= 0; i< lth; ++i){
			if (!drop[i]){
				putchar(sen[i]);
			}
		}
	}

	return 0;
}

标签：int,drop,POJ,1690,sen,include,sg,empty
来源： https://www.cnblogs.com/Idi0t-N3/p/14951330.html