solved: 20

Author: ryoppippi

code/20.valid-parentheses.ts

@@ -0,0 +1,29 @@
+// @leet start
+const PARENTIES = ['(', ')', '{', '}', '[', ']' ] as const
+type Parenty = typeof PARENTIES[number]
+
+function isValid(str: string): boolean {
+  const st: Parenty[] = []
+  const m = {
+    '{': '}',
+    '[': ']',
+    '(': ')'
+  }
+
+  for(const _s of str){
+    const s = _s as Parenty
+
+    /** 入ってるってことは開き括弧 */
+    if(m[s]!=null) st.push(m[s]);
+
+    
+    /* stackの一番上の要素と入ってきた閉じ括弧が同じか確認 */
+    else if(st.length>0 && st.at(-1) === s ) st.pop()
+
+    /* 違うならfalse */
+    else return false
+  }
+  /* stackが空ならtrue */
+  return st.length ===0
+};
+// @leet end