poj 2442 优先队列+多路归并 uva 11997

白书上的例题，很是经典。

poj 2442

#include <algorithm>
#include <iostream>
#include <cstring>
#include <cstdio>
#include <queue>
using namespace std;

const int M = 100;
const int N = 2000;
int a[M][N];

struct Node
{
    int j, v;
    Node(){}
    Node( int _j, int _v )
    {
        j = _j, v = _v;
    }
    bool operator < ( const Node & o ) const
    {
        return v > o.v;
    }
};

void merge_list( int * a, int * b, int len )
{
    priority_queue<Node> q;
    for ( int i = 0; i < len; i++ )
    {
        q.push( Node( 0, a[i] + b[0] ) );
    }
    for ( int i = 0; i < len; i++ )
    {
        Node node = q.top();
        q.pop();
        a[i] = node.v;
        if ( node.j + 1 < len )
        {
            q.push( Node( node.j + 1, node.v - b[node.j] + b[node.j + 1] ) );
        }
    }
}

int main ()
{
    int t;
    scanf("%d", &t);
    while ( t-- )
    {
        int m, n;
        scanf("%d%d", &m, &n);
        for ( int i = 0; i < m; i++ )
        {
            for ( int j = 0; j < n; j++ )
            {
                scanf("%d", &a[i][j]);
            }
            sort( a[i], a[i] + n );
        }
        for ( int i = 1; i < m; i++ )
        {
            merge_list( a[0], a[i], n );
        }
        for ( int i = 0; i < n; i++ )
        {
            printf("%d", a[0][i]);
            if ( i != n - 1 ) putchar(' ');
            else putchar('
');
        }
    }
    return 0;
}

uva 11997

#include <algorithm>
#include <iostream>
#include <cstring>
#include <cstdio>
#include <queue>
using namespace std;

const int N = 1000;
int a[N][N];

struct Node
{
    int j, v;
    Node(){}
    Node( int _j, int _v )
    {
        j = _j, v = _v;
    }
    bool operator < ( const Node & o ) const
    {
        return v > o.v;
    }
};

void merge_list( int * a, int * b, int len )
{
    priority_queue<Node> q;
    for ( int i = 0; i < len; i++ )
    {
        q.push( Node( 0, a[i] + b[0] ) );
    }
    for ( int i = 0; i < len; i++ )
    {
        Node node = q.top();
        q.pop();
        a[i] = node.v;
        if ( node.j + 1 < len )
        {
            q.push( Node( node.j + 1, node.v - b[node.j] + b[node.j + 1] ) );
        }
    }
}

int main ()
{
    int n;
    while ( scanf("%d", &n) != EOF )
    {
        for ( int i = 0; i < n; i++ )
        {
            for ( int j = 0; j < n; j++ )
            {
                scanf("%d", &a[i][j]);
            }
            sort( a[i], a[i] + n );
        }
        for ( int i = 1; i < n; i++ )
        {
            merge_list( a[0], a[i], n );
        }
        for ( int i = 0; i < n; i++ )
        {
            printf("%d", a[0][i]);
            if ( i != n - 1 ) putchar(' ');
            else putchar('
');
        }
    }
    return 0;
}