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。
import java.util.ArrayList;
public class Solution {
//B[i]=A[0]*A[1]*...*A[i-1]*A[i+1]*...*A[n-1]
//可以分成两部分计算
//先计算: B[i]=A[0]*A[1]*...*A[i-1]
//然后计算:B[i]*=A[i+1]*...*A[n-1]
public int[] multiply(int[] A) {
int[] result = new int[A.length];
int start = 1;
for (int i = 0; i < A.length; i++) {
result[i] = start;
start *= A[i];
}
start = 1;
for (int i = A.length - 1; i >= 0; i--) {
result[i] *= start;
start *= A[i];
}
return result;
}
}