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  1. #include <stdio.h>
  2. #include <stdlib.h>
  3. #include <string.h>
  4.  
  5. typedef struct {
  6.     char *data;
  7.     int top;
  8.     int capacity;
  9. } Stack;
  10.  
  11. Stack* createStack(int capacity) {
  12.     Stack* s = (Stack*)malloc(sizeof(Stack));
  13.     s -> capacity = capacity;
  14.     s -> top = -1;
  15.     s -> data = (char*)malloc(s -> capacity * sizeof(char));
  16.     return s;
  17. }
  18.  
  19. int isEmpty(Stack* s) {
  20.     return s -> top == -1;
  21. }
  22.  
  23. void push(Stack* s, char c) {
  24.     s -> data[++(s -> top)] = c;
  25. }
  26.  
  27. char pop(Stack* s) {
  28.     if(isEmpty(s)) return '\0';
  29.     return s -> data[(s -> top)--];
  30. }
  31.  
  32. void freeStack(Stack* s) {
  33.     free(s -> data);
  34.     free(s);
  35. }
  36.  
  37. int isMatching(char open, char close) {
  38.     return (open == '(' && close == ')') || (open == '[' && close == ']') || (open == '{' && close == '}');
  39. }
  40.  
  41. int isValidParentheses(const char *s) {
  42.     int len = strlen(s);
  43.     Stack *st = createStack(len);
  44.     for(int i = 0; i < len; i++) {
  45.         char c = s[i];
  46.         if(c == '(' || c == '[' || c == '{') {
  47.             push(st, c);
  48.         }
  49.         else if(c == ')' || c == ']' || c == '}') {
  50.             if(isEmpty(st)) {
  51.                 freeStack(st);
  52.                 return 0;
  53.             }
  54.             char top = pop(st);
  55.             if(!isMatching(top, c)) {
  56.                 freeStack(st);
  57.                 return 0;
  58.             }
  59.         }
  60.     }
  61.  
  62.     int result = isEmpty(st) ? 1 : 0;
  63.     freeStack(st);
  64.     return result;
  65. }
  66.  
  67. void vanimain() {
  68.     char *s = (char*)malloc(100005 * sizeof(char));
  69.     if(scanf("%100004s", s) == 1) {
  70.         printf("%d\n", isValidParentheses(s));
  71.     }
  72.     free(s);
  73. }
  74.  
  75. int main() {
  76.     vanimain();
  77.     return 0;
  78. }
Success #stdin #stdout 0s 5324KB
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(()[][]{}){}{}[][]({[]()})
stdout
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1
https://ideone.com/yUgCQM
Parentheses Sequence Validation Problem Using Stack
language:
C (gcc 8.3)
created:
1 day ago
visibility:
public

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