[codility]tape_equilibrium

http://codility.com/demo/take-sample-test/tapeequilibrium

简单题。记录到i为止的sum就可以了。O(n)。

// you can also use includes, for example:
// #include <algorithm>
int solution(vector<int> &A) {
    // write your code in C++98
    int total = 0;
    vector<int> sum;
    for (int i = 0; i < A.size(); i++) {
        total += A[i];
        sum.push_back(total);
    }
    int ans = 1 << 30;
    for (int i = 0; i < A.size() - 1; i++) {
        int tmp = (total - 2 * sum[i]);
        if (tmp < 0) tmp = -tmp;
        if (ans > tmp) ans = tmp;
    }
    return ans;
}