题目描述给定一个数组A[0,1,...,n-1],请构建一个数组B[0,1,...,n-1],其中B中的元素B[i]=A[0]*A[1]*...*A[i-1]*A[i+1]*...*A[n-1]。不能使用除法。
//B[i]=A[0]*A[1]*...*A[i-1]*A[i+1]*...*A[n-1]
//从左到右算 B[i]=A[0]*A[1]*...*A[i-1]
//从右到左算B[i]*=A[i+1]*...*A[n-1]
class Solution {
public:
vector<int> multiply(const vector<int>& A) {
int n=A.size();
vector<int> b(n);
int ret=1;
for(int i=0;i<n;ret*=A[i++]){
b[i]=ret;
}
ret=1;
for(int i=n-1;i>=0;ret*=A[i--]){
b[i]*=ret;
}
return b;
}
}; |
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