67 lines
1.5 KiB
Go
67 lines
1.5 KiB
Go
// File: coin_change.go
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// Created Time: 2023-07-23
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// Author: Reanon (793584285@qq.com)
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package chapter_dynamic_programming
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import "math"
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/* Coin change: Dynamic programming */
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func coinChangeDP(coins []int, amt int) int {
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n := len(coins)
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max := amt + 1
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// Initialize dp table
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dp := make([][]int, n+1)
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for i := 0; i <= n; i++ {
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dp[i] = make([]int, amt+1)
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}
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// State transition: first row and first column
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for a := 1; a <= amt; a++ {
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dp[0][a] = max
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}
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// State transition: the rest of the rows and columns
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for i := 1; i <= n; i++ {
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for a := 1; a <= amt; a++ {
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if coins[i-1] > a {
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// If exceeding the target amount, do not choose coin i
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dp[i][a] = dp[i-1][a]
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} else {
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// The smaller value between not choosing and choosing coin i
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dp[i][a] = int(math.Min(float64(dp[i-1][a]), float64(dp[i][a-coins[i-1]]+1)))
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}
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}
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}
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if dp[n][amt] != max {
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return dp[n][amt]
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}
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return -1
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}
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/* Coin change: Dynamic programming */
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func coinChangeDPComp(coins []int, amt int) int {
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n := len(coins)
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max := amt + 1
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// Initialize dp table
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dp := make([]int, amt+1)
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for i := 1; i <= amt; i++ {
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dp[i] = max
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}
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// State transition
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for i := 1; i <= n; i++ {
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// Traverse in order
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for a := 1; a <= amt; a++ {
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if coins[i-1] > a {
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// If exceeding the target amount, do not choose coin i
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dp[a] = dp[a]
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} else {
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// The smaller value between not choosing and choosing coin i
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dp[a] = int(math.Min(float64(dp[a]), float64(dp[a-coins[i-1]]+1)))
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}
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}
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}
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if dp[amt] != max {
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return dp[amt]
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}
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return -1
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}
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