8586 括号匹配检验
### 思路
1. **初始化栈**:创建一个空栈用于存储左括号。
2. **遍历字符串**:逐个字符检查:
- 如果是左括号(`(` 或 `[`),则入栈。
- 如果是右括号(`)` 或 `]`),则检查栈是否为空:
- 如果栈为空,说明缺少左括号,输出错误信息。
- 如果栈不为空,弹出栈顶元素并检查是否匹配:
- 如果匹配,继续检查下一个字符。
- 如果不匹配,输出错误信息。
3. **检查栈是否为空**:遍历结束后,如果栈为空,说明括号匹配;否则,说明缺少右括号。
### 伪代码
```
function InitStack(S):
allocate memory for S.base of size STACK_INIT_SIZE
S.top = S.base
S.stacksize = STACK_INIT_SIZE
return OK
function StackEmpty(S):
return S.top == S.base
function Push(S, e):
if S.top - S.base >= S.stacksize:
reallocate memory for S.base with size S.stacksize + STACKINCREMENT
S.top = S.base + S.stacksize
S.stacksize += STACKINCREMENT
S.top = e
S.top += 1
return OK
function Pop(S, e):
if S.top == S.base:
return ERROR
S.top -= 1
e = S.top
return OK
function check():
initialize stack s
read input string ch
p = ch
while *p:
if *p is '(' or '[':
Push(s, *p)
else if *p is ')' or ']':
if StackEmpty(s):
print "lack of left parenthesis"
exit(ERROR)
Pop(s, e)
if (*p is ')' and e is not '(') or (*p is ']' and e is not '['):
print "isn't matched pairs"
exit(ERROR)
p += 1
if StackEmpty(s):
print "matching"
else:
print "lack of right parenthesis"
```
### C++代码
#include <iostream>
#include <cstdlib>
using namespace std;typedef char SElemType;
#define OK 1
#define ERROR 0
#define TRUE 1
#define FALSE 0
typedef int Status;
#define STACK_INIT_SIZE 10
#define STACKINCREMENT 2struct SqStack {SElemType *base;SElemType *top;int stacksize;
};Status InitStack(SqStack &S) {S.base = (SElemType *)malloc(STACK_INIT_SIZE * sizeof(SElemType));if (!S.base) exit(ERROR);S.top = S.base;S.stacksize = STACK_INIT_SIZE;return OK;
}Status StackEmpty(SqStack S) {return S.top == S.base ? TRUE : FALSE;
}Status Push(SqStack &S, SElemType e) {if (S.top - S.base >= S.stacksize) {S.base = (SElemType *)realloc(S.base, (S.stacksize + STACKINCREMENT) * sizeof(SElemType));if (!S.base) exit(ERROR);S.top = S.base + S.stacksize;S.stacksize += STACKINCREMENT;}*S.top++ = e;return OK;
}Status Pop(SqStack &S, SElemType &e) {if (S.top == S.base) return ERROR;e = *--S.top;return OK;
}void check() {SqStack s;SElemType ch[80], *p, e;if (InitStack(s)) {cin >> ch;p = ch;while (*p) {switch (*p) {case '(':case '[':Push(s, *p);p++;break;case ')':case ']':if (!StackEmpty(s)) {Pop(s, e);if ((*p == ')' && e != '(') || (*p == ']' && e != '[')) {cout << "isn't matched pairs" << endl;exit(ERROR);} else {p++;break;}} else {cout << "lack of left parenthesis" << endl;exit(ERROR);}default:p++;}}if (StackEmpty(s))cout << "matching" << endl;elsecout << "lack of right parenthesis" << endl;}
}int main() {check();return 0;
}