SRM 586 DIV1 L1

可以化简为求n条线段的最大覆盖问题，需要注意的是对于实数而言。

#include <iostream>

#include <vector>

#include <string>

#include <queue>

#include <map>

#include <string.h>

using namespace std;



class PiecewiseLinearFunction {

private:

    map<int, int> Y2i;

    int value[100];

public:

    int maximumSolutions(vector <int> Y) {

        for (int i = 0; i < Y.size(); i++) {

            Y2i[Y[i]] = 0;

        }

        int no = 0;

        for (map<int, int>::iterator it = Y2i.begin(); it != Y2i.end(); it++) {

            //cout << it->first << endl;

            it->second = 2 * no++;

        }



        memset(value, 0, sizeof(value));



        for (int i = 0; i < Y.size() - 1; i++) {

            int d = Y[i + 1] - Y[i];

            if (d == 0) {

                return -1;

            } else {

                d = d / abs(d);

                int begin = Y2i[Y[i]];

                int end = Y2i[Y[i + 1]];

                while (begin != end) {

                    value[begin]++;

                    begin += d;

                }

            }

        }

        value[Y2i[Y.back()]]++;



        int ans = 0;

        for (int i = 0; i < 100; i++) {

            ans = max(ans, value[i]);

        }

        return ans;

    }

};