题解 | #点击消除#

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#define MAXSIZE 300001
struct stack {
    char data[MAXSIZE];
    int top;
};
void push(struct stack* stac, char temp) {
    if (stac->top != MAXSIZE - 1) {
        stac->data[++stac->top] = temp;
    }
}
void pop(struct stack* stac) {
    if (stac->top != -1) {
        stac->data[stac->top--];
    }
}
int main() {
    struct stack* stac = (struct stack*)malloc(sizeof(struct stack));
    stac->top = -1;
    char* s = (char *)malloc(sizeof(char)*MAXSIZE);
    scanf("%s",s);
    int i = 0;
    while(s[i]!='\0'){
	  //相同不入栈，且出栈
        if(s[i]==stac->data[stac->top]&&stac->top!=-1) pop(stac);
	  //不同入栈
        else push(stac,s[i]);
        i++;
    }
    if(stac->top == -1) printf("0");
    else{
        char* temp = (char *)malloc(sizeof(char)*((stac->top)+2));
        int count = stac->top;
        for(int i = 0;i<=count;i++){
            temp[stac->top+1] = stac->data[stac->top--];
        }
        for(int i = 0;i<=count;i++){
            printf("%c",temp[i]);
        }
    }
}