Day8 - G - Bound Found ZOJ

Signals of most probably extra-terrestrial origin have been received and digitalized by The Aeronautic and Space Administration (that must be going through a defiant phase: "But I want to use feet, not meters!"). Each signal seems to come in two parts: a sequence of n integer values and a non-negative integer t. We'll not go into details, but researchers found out that a signal encodes two integer values. These can be found as the lower and upper bound of a subrange of the sequence whose absolute value of its sum is closest to t.

You are given the sequence of n integers and the non-negative target t. You are to find a non-empty range of the sequence (i.e. a continuous subsequence) and output its lower index l and its upper index u. The absolute value of the sum of the values of the sequence from the l-th to the u-th element (inclusive) must be at least as close to t as the absolute value of the sum of any other non-empty range.

Input

The input file contains several test cases. Each test case starts with two numbers n and k. Input is terminated by n = k = 0. Otherwise, 1 <= n <= 100000 and there follow n integers with absolute values <= 10000 which constitute the sequence. Then follow k queries for this sequence. Each query is a target t with 0 <= t <= 1000000000.

Output

For each query output 3 numbers on a line: some closest absolute sum and the lower and upper indices of some range where this absolute sum is achieved. Possible indices start with 1 and go up to n.

Sample Input

5 1
-10 -5 0 5 10
3
10 2
-9 8 -7 6 -5 4 -3 2 -1 0
5 11
15 2
-1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1 -1
15 100
0 0

Sample Output

5 4 4
5 2 8
9 1 1
15 1 15
15 1 15

思路：维护前缀和，排序后维护双指针取值，细节直接看代码

using namespace std;

#define lowbit(x) ((x)&(-x))

typedef long long LL;

typedef pair<LL, LL> PLL;

const int maxm = 1e5+;

int n, k;

LL C[maxm];

void add(int x, int val) {

    for(; x <= n; x += lowbit(x))

        C[x] += val;

}

LL getsum(int x) {

    LL ret = ;

    for(; x; x -= lowbit(x))

        ret += C[x];

    return ret;

}

struct Node {

    LL val;

    int id;

    bool operator<(const Node &a) const {

        return val < a.val;

    }

} Nodes[maxm];

int main() {

    ios::sync_with_stdio(false), cin.tie();

    int t, val;

    while(cin >> n >> k && n+k) {

        memset(C, , sizeof(C));

        for(int i = ; i <= n; ++i) {

            cin >> val;

            add(i, val);

            Nodes[i] = {getsum(i), i};

        }

        Nodes[].id = , Nodes[].val = ;

        sort(Nodes,Nodes++n);

        while(k--) {

            int l = , r = , ansL, ansR;

            LL ans, t, diff = 0x3f3f3f3f;

            cin >> t;

            while(l <= n && r <= n) {

                LL val = Nodes[r].val - Nodes[l].val;

                if(abs(val - t) < diff) {

                    ans = val;

                    diff = abs(val-t);

                    ansL = min(Nodes[l].id+,Nodes[r].id+);

                    ansR = max(Nodes[l].id, Nodes[r].id);

                }

                if(val > t)

                    l++;

                else if(val < t)

                    r++;

                else break;

                if(l == r) r++;

            }

            cout << ans << " " << ansL << " " << ansR << "\n";

        }

    }

    return ;

}

巴特西

Day8 - G - Bound Found ZOJ - 1964

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