.\821.shortest-distance-to-a-character ok

侯利朋 · 侯利朋 · commit 149dc3d4e291 · 2019-08-31T19:18:40.000+08:00
diff --git a/821.shortest-distance-to-a-character.go b/821.shortest-distance-to-a-character.go
@@ -0,0 +1,32 @@
+/*
+ * @lc app=leetcode id=821 lang=golang
+ *
+ * [821] Shortest Distance to a Character
+ */
+// 0 ms
+// 遍历两遍
+func shortestToChar(S string, C byte) []int {
+
+	rtn := make([]int, len(S))
+
+	// 左往右
+	pri := -len(S) // 前一个C的位置, 初始为-len(S), 则rtn中记录的值肯定比右往左的时候大
+	for i := 0; i < len(S); i++ {
+		if S[i] == C {
+			pri = i
+		}
+		rtn[i] = i - pri
+	}
+
+	// 右往左
+	next := len(S) * 2 // 2倍长度，保证右往左的时候最大
+	for i := len(S) - 1; i >= 0; i-- {
+		if S[i] == C {
+			next = i
+		}
+		if rtn[i] > next-i {
+			rtn[i] = next - i
+		}
+	}
+	return rtn
+}
