Codeforces Round #241 (Div. 2) 解题报告

Problem A Guess a number!

这道题比较容易错注意最小值一定小于-1e9，最大值大于1e9

代码如下:

/**************************************************
 * Author     : xiaohao Z
 * Blog     : http://www.cnblogs.com/shu-xiaohao/
 * Last modified : 2014-04-13 15:56
 * Filename     : Codeforce_241_2_E.cpp
 * Description     : 
 * ************************************************/

#include <iostream>
#include <cstdio>
#include <cstring>
#include <cstdlib>
#include <cmath>
#include <algorithm>
#include <queue>
#include <stack>
#include <vector>
#include <set>
#include <map>
#define MP(a, b) make_pair(a, b)
#define PB(a) push_back(a)

using namespace std;
typedef long long ll;
typedef pair<int, int> pii;
typedef pair<unsigned int,unsigned int> puu;
typedef pair<int, double> pid;
typedef pair<ll, int> pli;
typedef pair<int, ll> pil;

const int INF = 0x3f3f3f3f;
const double eps = 1E-6;

int main()
{
    freopen("in.txt", "r", stdin);

    int n, x, l, r;
    string op, c;
    while(cin >> n){
        l = -INF;
        r = INF;
        for(int i=0; i<n; i++){
            cin >> op >> x >> c;
            if(c == "Y"){
                if(op == "<"){
                    r = min(r, x-1);
                }else if(op == "<="){
                    r = min(r, x);
                }else if(op == ">"){
                    l = max(l, x+1);
                }else{
                    l = max(l, x);
                } 
            }else{
                if(op == "<"){
                    l = max(l, x);
                }else if(op == "<="){
                    l = max(l, x+1);
                }else if(op == ">"){
                    r = min(r, x);
                }else{
                    r = min(r, x-1);    
                } 
            }
        }
        if(l > r) cout << "Impossible" << endl;
        else cout << (l+r)/2 << endl;
    }
    return 0;
}

Problem B Art Union

递推一下即可sum[i][j] = max(sum[i-1][j], sum[i][j-1])+a[i][j];

代码如下：

/**************************************************
 * Author     : xiaohao Z
 * Blog     : http://www.cnblogs.com/shu-xiaohao/
 * Last modified : 2014-04-13 15:56
 * Filename     : Codeforce_241_2_B.cpp
 * Description     : 
 * ************************************************/

#include <iostream>
#include <cstdio>
#include <cstring>
#include <cstdlib>
#include <cmath>
#include <algorithm>
#include <queue>
#include <stack>
#include <vector>
#include <set>
#include <map>
#define MP(a, b) make_pair(a, b)
#define PB(a) push_back(a)

using namespace std;
typedef long long ll;
typedef pair<int, int> pii;
typedef pair<unsigned int,unsigned int> puu;
typedef pair<int, double> pid;
typedef pair<ll, int> pli;
typedef pair<int, ll> pil;

const int INF = 0x3f3f3f3f;
const double eps = 1E-6;
int a[50000+10][10], sum[50000+10][10];
int n, m;

void debug(){
    for(int i=0; i<=n; i++){
        for(int j=0; j<=m; j++){
            cout << sum[i][j] << ' ';
        }cout << endl;
    }cout << endl;
}

int main()
{
//    freopen("in.txt", "r", stdin);

    while(cin >> n >> m){
        memset(a, 0, sizeof a);
        memset(sum, 0, sizeof sum);
        for(int i=1; i<=n; i++)
            for(int j=1; j<=m; j++)
                cin >> a[i][j];
        for(int i=1; i<=m; i++) sum[1][i] = sum[1][i-1] + a[1][i];
        for(int i=1; i<=n; i++) sum[i][1] = sum[i-1][1] + a[i][1];
        for(int i=2; i<=n; i++){
            for(int j=2; j<=m; j++){
                sum[i][j] = max(sum[i-1][j], sum[i][j-1])+a[i][j];
            }
        }
        for(int i=1; i<=n; i++){
            cout << sum[i][m] << ' ';
        }
        cout << endl;
    }
    return 0;
}

Problem C Booking System

贪心尽量让小的桌子坐下钱多的人就可以了。

代码如下：

/**************************************************
 * Author     : xiaohao Z
 * Blog     : http://www.cnblogs.com/shu-xiaohao/
 * Last modified : 2014-04-13 15:56
 * Filename     : Codeforce_241_2_C.cpp
 * Description     : 
 * ************************************************/

#include <iostream>
#include <cstdio>
#include <cstring>
#include <cstdlib>
#include <cmath>
#include <algorithm>
#include <queue>
#include <stack>
#include <vector>
#include <set>
#include <map>
#define MP(a, b) make_pair(a, b)
#define PB(a) push_back(a)

using namespace std;
typedef long long ll;
typedef pair<int, int> pii;
typedef pair<unsigned int,unsigned int> puu;
typedef pair<int, double> pid;
typedef pair<ll, int> pli;
typedef pair<int, ll> pil;

const int INF = 0x3f3f3f3f;
const double eps = 1E-6;
const int LEN = 1010;
struct P{
    int a, b, num;
}p[LEN];
struct D{
    int a, num;
}d[LEN];

bool cmp(P a, P b){
    if(a.a != b.a)return a.b > b.b;
    else return a.a < b.a;
}

bool cmp2(D a, D b){
    return a.a < b.a;
}

int main()
{
//    freopen("in.txt", "r", stdin);

    int n, m;
    while(cin >> n){
        for(int i=0; i<n; i++){
            cin >> p[i].a >> p[i].b;
            p[i].num = i;
        }
        cin >> m;
        for(int i=0; i<m; i++){
            cin >> d[i].a;
            d[i].num = i;
        }
        sort(d, d+m,cmp2);
        sort(p, p+n, cmp);
        int ans = 0, cnt = 0, f[LEN];
        memset(f, -1, sizeof f);
        for(int i=0; i<m; i++){
            int tmp = -1;
            for(int j=0; j<n; j++){
                if(f[j] >= 0) continue;
                if(d[i].a >= p[j].a && (tmp == -1 || p[j].b > p[tmp].b)){
                    tmp = j;
                }
            }
            if(tmp == -1) continue;
            cnt ++;
            f[tmp] = d[i].num;
            ans += p[tmp].b;
        }
        cout << cnt << ' ' << ans << endl;
        for(int i=0; i<n; i++){
            if(f[i] >= 0){
                cout << p[i].num+1 << ' ' << f[i]+1 << endl;
            }
        }
    }
    return 0;
}