c_cpp 给定一组正负整数，重新排列它，使得一端为正整数，另一端为负整数。

Posted 2021-05-14

// without keep the order
void rearrange(int A[], int N) {
    int low = 0, high = N-1;
    while(low < high) {
        while(low < N && A[low] < 0) low++;
        if(low == N) return;
        while(high >= 0 && A[high] > 0) high--;
        if(high < 0) return;
        swap(A[low], A[high]);
        low++;
        high--;
    }
}

// keep the order
void rearrange(int A[], int N) {
    int *B = new int[N];
    int j=0;
    for(int i=0; i<N; i++)
        if(A[i] < 0) B[j++] = A[i];
    for(int i=0; i<N; i++)
        if(A[i] > 0) B[j++] = A[i];
    for(int i=0; i<N; i++)
        A[i] = B[i];
    delete [] B;
}