20. 有效的括号 - 力扣（LeetCode）

错误记录

#include<stddef.h>
#include<stdlib.h>
#include<assert.h>
#include<stdbool.h>typedef char STDataType;typedef struct Stack
{STDataType* a;int capacity;int top;
} Stack;void STInit(Stack* st);
void STDestroy(Stack* st);void STPush(Stack* st, STDataType x);
STDataType STPop(Stack* st);
STDataType STTop(Stack* st);
int STSize(Stack* st);
bool STEmpty(Stack* st);void STInit(Stack* st)
{assert(st);st->a = NULL;st->capacity = st->top = 0;
}void STDestroy(Stack* st)
{assert(st);free(st->a);st->a = NULL;st->capacity = st->top =  0;
}void STPush(Stack* st, STDataType x)
{assert(st);//checkcapacityif (st->capacity == st->top){int newcapacity = st->capacity == 0 ? 4 : st->capacity * 2;STDataType* temp = (STDataType*)realloc(st->a, sizeof(STDataType) * newcapacity);if (NULL == temp){perror("realloc failed");exit(-1);}st->a = temp;st->capacity = newcapacity;}st->a[st->top] = x;++st->top;
}STDataType STPop(Stack* st)
{assert(st);assert(st->top);STDataType ret = STTop(st);--st->top;return ret;
}STDataType STTop(Stack* st)
{assert(st);assert(st->top);return st->a[st->top - 1];
}int STSize(Stack* st)
{return st->top;
}bool STEmpty(Stack* st)
{return st->top == 0;
}bool isValid(char* s)
{Stack st;STInit(&st);int i = 0;while(*s){if(*s == '(' || *s == '[' || *s == '{')STPush(&st, *s);else{if((STPop(&st) == '(' && *s != ')') ||(STPop(&st) == '[' && *s != ']') ||(STPop(&st) == '{' && *s != '}')){STDestroy(&st);return false;}}++s;}STDestroy(&st);return true;
}

 

这里比较三次直接出了3次栈，应该只出一次比较三次。

修改成下面这样：

之后在" ( "和" ) "又分别翻车了，加了下面两句判断。

最终提交

#include <assert.h>
#include <stdbool.h>
#include <stddef.h>
#include <stdlib.h>typedef char STDataType;typedef struct Stack {STDataType* a;int capacity;int top;
} Stack;void STInit(Stack* st);
void STDestroy(Stack* st);void STPush(Stack* st, STDataType x);
STDataType STPop(Stack* st);
STDataType STTop(Stack* st);
int STSize(Stack* st);
bool STEmpty(Stack* st);void STInit(Stack* st) {assert(st);st->a = NULL;st->capacity = st->top = 0;
}void STDestroy(Stack* st) {assert(st);free(st->a);st->a = NULL;st->capacity = st->top = 0;
}void STPush(Stack* st, STDataType x) {assert(st);// checkcapacityif (st->capacity == st->top) {int newcapacity = st->capacity == 0 ? 4 : st->capacity * 2;STDataType* temp =(STDataType*)realloc(st->a, sizeof(STDataType) * newcapacity);if (NULL == temp) {perror("realloc failed");exit(-1);}st->a = temp;st->capacity = newcapacity;}st->a[st->top] = x;++st->top;
}STDataType STPop(Stack* st) {assert(st);assert(st->top);STDataType ret = STTop(st);--st->top;return ret;
}STDataType STTop(Stack* st) {assert(st);assert(st->top);return st->a[st->top - 1];
}int STSize(Stack* st) { return st->top; }bool STEmpty(Stack* st) { return st->top == 0; }bool isValid(char* s) {Stack st;STInit(&st);int i = 0;while (*s) {if (*s == '(' || *s == '[' || *s == '{')STPush(&st, *s);else{if(STEmpty(&st)){STDestroy(&st);return false;}char topval = STPop(&st);if ((topval == '(' && *s != ')') ||(topval == '[' && *s != ']') ||(topval == '{' && *s != '}')){STDestroy(&st);return false;}}++s;}if(!STEmpty(&st)) return false;STDestroy(&st);return true;
}

修改日志

2024/6/12

一处return的时候忘记调用STDestroy，有内存泄漏风险，补上了。

把变量top名称改成了topval，避免与Stack的成员top混杂，增强代码可读性。