leetcode 403

leetcode/403/403.go

@@ -0,0 +1,36 @@
+
+fun canCross(stones []int) bool {
+    n := len(stones)
+
+    dp := make([]bool, n)
+    vis := make(map[[2]int]struct{})
+
+    var jump func (pos int, from int)
+    jump = func (pos int, from int) {
+        if pos <= from {
+            return
+        }
+        if _, e := vis[[2]int{pos, from}]; e {
+            return
+        }
+
+        idx := sort.SearchInts(stones, pos)
+        // fmt.Println(pos, from, stones)
+
+        if idx < n && stones[idx] == pos {
+            dp[idx] = true
+            vis[[2]int{pos, from}] = struct{}{}
+
+            d := pos - from
+            jump(pos + d - 1, pos)
+            jump(pos + d, pos)
+            jump(pos + d + 1, pos)
+        }
+    }
+
+    if stones[1] - stones[0] == 1 {
+        jump(stones[1], stones[0])
+        return dp[n-1]
+    } 
+    return false
+}