【leetcode】322. 零钱兑换

 

int cmp(const void* a, const void* b){
    return *(int*)b - *(int*)a;
}
void recursion(int* coins,int coinsSize,int amount,int cur,int sum,int cnt,int* minCnt){
    if(cur==coinsSize){
        if(sum==amount)
            *minCnt=cnt;
        return;
    }
    int len=(amount-sum)/coins[cur];
    for (int i=len; i>=0 && cnt+i<*minCnt; i--){
        if(cur==coinsSize-1 && sum+i*coins[cur]<amount)
            break;
        recursion(coins,coinsSize,amount,cur+1,sum+i*coins[cur],cnt+i,minCnt);
    }
}
int coinChange(int* coins, int coinsSize, int amount){
    int minCnt=2147483647;
    qsort(coins,coinsSize,sizeof(int),cmp);
    recursion(coins,coinsSize,amount,0,0,0,&minCnt);
    return (minCnt==2147483647)?-1 :minCnt;
}