[Codeforces]B. Lorry

time limit :per test2 seconds
memory limit :per test64 megabytes
inputstandard: input
outputstandard: output
A group of tourists is going to kayak and catamaran tour. A rented lorry has arrived to the boat depot to take kayaks and catamarans to the point of departure. It’s known that all kayaks are of the same size (and each of them occupies the space of 1 cubic metre), and all catamarans are of the same size, but two times bigger than kayaks (and occupy the space of 2 cubic metres).

Each waterborne vehicle has a particular carrying capacity, and it should be noted that waterborne vehicles that look the same can have different carrying capacities. Knowing the truck body volume and the list of waterborne vehicles in the boat depot (for each one its type and carrying capacity are known), find out such set of vehicles that can be taken in the lorry, and that has the maximum total carrying capacity. The truck body volume of the lorry can be used effectively, that is to say you can always put into the lorry a waterborne vehicle that occupies the space not exceeding the free space left in the truck body.

Input
The first line contains a pair of integer numbers n and v (1 ≤ n ≤ 105; 1 ≤ v ≤ 109), where n is the number of waterborne vehicles in the boat depot, and v is the truck body volume of the lorry in cubic metres. The following n lines contain the information about the waterborne vehicles, that is a pair of numbers ti, pi (1 ≤ ti ≤ 2; 1 ≤ pi ≤ 104), where ti is the vehicle type (1 – a kayak, 2 – a catamaran), and pi is its carrying capacity. The waterborne vehicles are enumerated in order of their appearance in the input file.

Output
In the first line print the maximum possible carrying capacity of the set. In the second line print a string consisting of the numbers of the vehicles that make the optimal set. If the answer is not unique, print any of them.

Examples
input
3 2
1 2
2 7
1 3
output
7
2

思路：对ka,ca的集合capacity分别进行从大到小的排序，然后先用体积为1的ka将体积填充完，最后用体积为2的ca进行置换，置换的条件是ca的capacity大于两个ka的总capacity。

#include <cstdio>#include <vector>#include <algorithm>#include <iostream>using namespace std;struct vehicle {    int index;    int capacity;};int number, lorry_vol;int max_capacity = 0;vector<vehicle> ka, ca;bool cmp(const struct vehicle& A, const struct vehicle& B){    return A.capacity > B.capacity;}int main() {    scanf("%d%d", &number, &lorry_vol);    for (int i = 0; i < number; ++i) {        vehicle temp;        temp.index = i + 1;        int type;        scanf("%d%d", &type, &temp.capacity);        type == 1 ? ka.push_back(temp) : ca.push_back(temp);    }    sort(ka.begin(), ka.end(), cmp);    sort(ca.begin(), ca.end(), cmp);    vector<vehicle> temp_res;    vector<vehicle> res;    int volume_cur = 0;    // select ka    for (int i = 0; i < ka.size(); ++i) {        if (volume_cur + 1 <= lorry_vol) {            temp_res.push_back(ka[i]);            volume_cur++;        }        else {            break;        }    }    int last_ka_index_in_res = temp_res.size() - 1; // in temp_res index    int first_ca_index_in_ca = -1;    // select ca    for (int i = 0; i < ca.size(); ++i) {        if (volume_cur + 2 <= lorry_vol) {            temp_res.push_back(ca[i]);            res.push_back(ca[i]);            volume_cur += 2;        }        else {            first_ca_index_in_ca = i;            break;        }    }    int remain_vol = lorry_vol - volume_cur;    // replace ka with ca     if (first_ca_index_in_ca != -1) {        for (int now = last_ka_index_in_res; now >= 1; ) {            if (remain_vol > 0 && temp_res[now].capacity < ca[first_ca_index_in_ca].capacity) {                remain_vol--;                res.push_back(ca[first_ca_index_in_ca]);                now--;                last_ka_index_in_res--;                first_ca_index_in_ca++;                continue;            }            int last = now - 1;            if (temp_res[now].capacity + temp_res[last].capacity < ca[first_ca_index_in_ca].capacity) {                res.push_back(ca[first_ca_index_in_ca]);                now -= 2;                last_ka_index_in_res -= 2;                first_ca_index_in_ca++;                if (first_ca_index_in_ca >= ca.size())                    break;            }            else {                break;            }        }        if (last_ka_index_in_res == 0&&remain_vol > 0) {            if (temp_res[last_ka_index_in_res].capacity < ca[first_ca_index_in_ca].capacity) {                last_ka_index_in_res--;                res.push_back(ca[first_ca_index_in_ca]);                first_ca_index_in_ca++;            }        }    }    for (int i = 0; i <= last_ka_index_in_res; ++i) {        res.push_back(temp_res[i]);    }    for (int i = 0; i < res.size(); ++i) {        max_capacity += res[i].capacity;    }    printf("%d\n", max_capacity);    for (int i = 0; i < res.size(); ++i) {        printf("%d ", res[i]);    }    printf("\n");    return 0;}