动态规划
public int coinChange(int[] coins, int amount) {
if(coins.length == 0){
return -1;
}
int[] memo = new int[amount+1];
Arrays.fill(memo,amount+1);
memo[0] = 0;
for(int i = 1; i <= amount;i++){
for(int j = 0;j < coins.length;j++){
if(i - coins[j] >= 0){
memo[i] = Math.min(memo[i],memo[i-coins[j]] + 1);
}
}
}
return memo[amount] == (amount+1) ? -1 : memo[amount];
}
记忆法
int[] memo;
public int coinChange(int[] coins, int amount) {
if(coins.length == 0){
return -1;
}
memo = new int[amount];
return findWay(coins,amount);
}
public int findWay(int[] coins,int amount){
if(amount < 0){
return -1;
}
if(amount == 0){
return 0;
}
if(memo[amount-1] != 0){
return memo[amount-1];
}
int min = Integer.MAX_VALUE;
for(int i = 0;i < coins.length;i++){
int res = findWay(coins,amount-coins[i]);
if(res >= 0 && res < min){
min = res + 1;
}
}
memo[amount-1] = (min == Integer.MAX_VALUE ? -1 : min);
return memo[amount-1];
}
作者:sugar666
链接:https://leetcode-cn.com/problems/coin-change/solution/javadi-gui-ji-yi-hua-sou-suo-dong-tai-gui-hua-by-s/
递归 超时
int res = Integer.MAX_VALUE;
public int coinChange(int[] coins, int amount) {
if(coins.length == 0){
return -1;
}
findWay(coins,amount,0);
if(res == Integer.MAX_VALUE){
return -1;
}
return res;
}
public void findWay(int[] coins,int amount,int count){
if(amount < 0){
return;
}
if(amount == 0){
res = Math.min(res,count);
}
for(int i = 0;i < coins.length;i++){
findWay(coins,amount-coins[i],count+1);
}
}
作者:sugar666
链接:https://leetcode-cn.com/problems/coin-change/solution/javadi-gui-ji-yi-hua-sou-suo-dong-tai-gui-hua-by-s/