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Posted 2021-04-18 Coding鐨勫摂鍝斿彣鍙?/a>

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Map<Integer,Integer> map = new HashMap<>(); public int coinChange(int[] coins, int amount) { if(amount <= 0){ return 0; } return find_h(coins,amount); } private int find_h(int[] nums,int amount){ if(amount <0){ return -1; } if(amount == 0){ return 0; } if(map.containsKey(amount)){ return map.get(amount); } int count=Integer.MAX_VALUE; for(int num:nums){ if(num > amount){ continue; } int solu=find_h(nums,amount-num); if(solu>=0){ count = Math.min(count,solu+1); }        } if(count == Integer.MAX_VALUE){ count =-1; } map.put(amount,count); return map.get(amount); }

馃檵瑙ｆ硶浜岋細鍔ㄦ€佽鍒掋€愯嚜涓婅€屼笅銆?/span>

馃檱鎬濊矾锛?/span>

鐘舵€佸畾涔?/span>锛?/span>F(S)锛屽噾榻愭€婚噾棰漇锛岄渶瑕佺殑鏈€灏忕‖甯佹暟銆?/p>

鐘舵€佽浆绉绘柟绋?/span>锛?/span>F(S) = F(S-coins[i]) + 1銆?/span>

public int coinChange(int[] coins, int amount) { if (amount < 1) return 0; return coinChange_h(coins, amount,new int[amount+1]);}private int coinChange_h(int[] coins, int amount,int[] count) { if (amount < 0) return -1; if (amount == 0) return 0; if (count[amount] != 0) return count[amount]; int min = Integer.MAX_VALUE; for (int coin : coins) { int res = coinChange_h(coins, amount - coin,count); if (res >= 0 ) min = Math.min(1 + res,min); } count[amount] = min == Integer.MAX_VALUE ? -1:min; return count[amount];}

馃檵瑙ｆ硶涓夛細鍔ㄦ€佽鍒掋€愯嚜涓嬭€屼笂銆?/strong>

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鐘舵€佸畾涔?/span>锛歞p[j]锛屽噾榻愭€婚噾棰漥锛岄渶瑕佺殑鏈€灏忕‖甯佹暟銆?/p>

鐘舵€佽浆绉绘柟绋?/span>锛歞p[i][j]= min(dp[i][j],dp[i](j-coins[i]) + 1)銆傚噾榻愭€婚噾棰漥闇€瑕佺殑鏈€灏忕‖甯佹暟锛屽綋鍦癷涓‖甯侀€夋垨鑰呬笉閫変袱绉嶆儏鍐点€?/span>

public int coinChange_2(int[] coins, int amount) { if (amount < 1) return 0; int[] dp = new int[amount+1]; Arrays.fill(dp,amount+1); //杩欏効瑙ｉ噴涓嬩负鍟ラ粯璁ゅ～鍏卆mount+1锛屽噾榻恆mount鏈€澶氫篃灏辨槸闈㈠€间负1鐨勬暟鎬昏鐢╝mount涓紝 // 鎵€浠ユ渶灏戜釜鏁颁竴瀹氭槸<amount+1鐨?/span> dp[0]=0; for(int j=1;j<=amount;j++){ for(int num:coins){ if(num <= j){ dp[j]=Math.min(dp[j],dp[j-num]+1); } } } return dp[amount]==amount+1?-1:dp[amount];}

澶嶆潅搴﹀垎鏋?/span>

• 鏃堕棿澶嶆潅搴︼細O(SN)锛氳繖閲孲鏄€婚噾棰濓紝N鏄彁渚涚殑涓嶅悓闈㈤鏁帮紝鍗虫暟缁勯暱搴︺€傛垜浠璁＄畻O(S)涓笉鍚屾€婚噾棰濓紝瀵规瘡娆＄殑鎬婚噾棰濋渶瑕丯涓潰棰濇潵杞Щ鐘舵€侊紝涓€鍏遍渶瑕丱(SN)鐨勬椂闂村鏉傚害銆?/span>

• 绌洪棿澶嶆潅搴︼細O(S)锛屾垜浠娇鐢ㄤ簡涓€涓猄+1鐨刣p鏁扮粍銆?/span>

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涓嶇Н璺锛屾棤浠ヨ嚦鍗冮噷銆?/strong>

鏂囩珷鏈夊府鍔╃殑璇濓紝鐐逛釜杞彂銆佸湪鐪嬪憲銆?/strong>
璋㈣阿鏀寔鍝?(*^__^*)

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