Given a string containing just the characters ‘(‘, ‘)’, ‘{‘, ‘}’, ‘[’ and ‘]’, determine if the input string is valid.
The brackets must close in the correct order, “()” and “()[]{}” are all valid but “(]” and “([)]” are not.
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class Solution {public: bool isValid(string s) { char stack[5000]; int top = 0; int len = s.size(); for(int i = 0 ; i < len;i++ ){ if(!top){ stack[top++] = s[i]; } else{ switch(s[i]){ case '(': case '[': case '{':stack[top++] = s[i];break; case ')': if(stack[top-1] == '('){ top--; } else{ return false; } break; case ']': if(stack[top-1] == '['){ top--; } else{ return false; } break; case '}': if(stack[top-1] == '{'){ top--; } else{ return false; } break; default:break; } } } if(top == 0){ return true; } return false; }};新聞熱點
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