add new solutions

solutions/3/q322/solution.go

@@ -0,0 +1,31 @@
+package q322
+
+// Note: The cache size only needs to be min(max(coins), amount).
+
+func coinChange(coins []int, amount int) int {
+	if amount == 0 {
+		return 0
+	}
+
+	cache := make([]int, amount+1)
+	cache[0] = amount + 1
+	for p := 1; p < len(cache); p *= 2 {
+		copy(cache[p:], cache[:p]) // fill with MAX+1
+	}
+	cache[0] = 0
+
+	for i := 1; i < len(cache); i++ {
+		for _, c := range coins {
+			if (i - c) < 0 {
+				continue
+			}
+			cache[i] = min(cache[i], cache[i-c]+1)
+		}
+	}
+	if cache[amount] > amount {
+		return -1
+	}
+	return cache[amount]
+}
+
+var _ = coinChange