SRM 453.5 DIV1 总结

今天的题有点简单呀。。

250p:

暴搜。。。

450p:

对于边不相交的n个点 (n >= 3)最多有(n-3)*3 + 3条边。

250p:

#include <cstdio>
#include <cstring>
#include <cctype>
#include <cstdlib>
#include <cmath>
#include <ctime>
#include <iostream>
#include <map>
#include <set>
#include <list>
#include <sstream>
#include <queue>
#include <deque>
#include <stack>
#include <vector>
#include <bitset>
#include <algorithm>
using namespace std;
#define clr(a, x) memset(a, x, sizeof(a))
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define REP(i,a,b) for(int i=a;i<=b;i++)
template <class T> void checkmax(T &t, T x) { if (x > t) t = x; }
template <class T> void checkmin(T &t, T x) { if (x < t) t = x; }
template <class T> void _checkmax(T &t, T x) { if (t == -1 || x > t) t = x; }
template <class T> void _checkmin(T &t, T x) { if (t == -1 || x < t) t = x; }
typedef long long ll;
class MazeMaker {
    public:
    int longestPath(vector <string> maze, int startRow, int startCol, vector <int> moveRow, vector <int> moveCol)  ;


};

struct Point {
    int x, y, step;
    Point() {}
    Point(int x, int y, int step) : x(x), y(y), step(step) {}
}cur;

int dx[55], dy[55], n, m, tot;
bool vis[55][55];
char s[55][55];
queue <Point> q;

int bfs(int x, int y) {
    q.push(Point(x, y, 0));
    memset(vis, 0, sizeof(vis));
    vis[x][y] = 1;
    int ans = 0;
    while(!q.empty()) {
        cur = q.front(); q.pop();
        x = cur.x, y = cur.y;
        int step = cur.step;
        ans = step;
        for(int i = 0;i < tot; i++) {
            int xx = x + dx[i];
            int yy = y + dy[i];
            if(xx < 0 || xx >= n || yy < 0 || yy >= m || vis[xx][yy] || s[xx][yy] == 'X')
                continue;
            vis[xx][yy] = 1;
            q.push(Point(xx, yy, step+1));
        }
    }
    for(int i = 0;i < n; i++)
        for(int j = 0;j < m; j++)
        if(s[i][j] == '.' && !vis[i][j])
        return -1;
    return ans;
}

int MazeMaker::longestPath(vector <string> maze, int startRow, int startCol, vector <int> moveRow, vector <int> moveCol) {
    int i, j;
    n = maze.size();
    m = maze[0].size();
    for(i = 0;i < n; i++) {
        for(j = 0;j < m; j++) {
            s[i][j] = maze[i][j];
        }
    }
    tot = moveRow.size();
    for(i = 0;i < tot; i++) {
        dx[i] = moveRow[i];
        dy[i] = moveCol[i];
    }
    int ans = bfs(startRow, startCol);
    return ans;
}


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450p:

#include <cstdio>
#include <cstring>
#include <cctype>
#include <cstdlib>
#include <cmath>
#include <ctime>
#include <iostream>
#include <map>
#include <set>
#include <list>
#include <sstream>
#include <queue>
#include <deque>
#include <stack>
#include <vector>
#include <bitset>
#include <algorithm>
using namespace std;
#define clr(a, x) memset(a, x, sizeof(a))
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define REP(i,a,b) for(int i=a;i<=b;i++)
template <class T> void checkmax(T &t, T x) { if (x > t) t = x; }
template <class T> void checkmin(T &t, T x) { if (x < t) t = x; }
template <class T> void _checkmax(T &t, T x) { if (t == -1 || x > t) t = x; }
template <class T> void _checkmin(T &t, T x) { if (t == -1 || x < t) t = x; }
typedef long long ll;
class PlanarGraphShop {
    public:
    int bestCount(int N) ;


};

#define INF  11111111
bool vis[50005];

void init(int n) {
    memset(vis, 0, sizeof(vis));
    int dep = 1;
    while(dep*dep*dep <= n) {
        int limit = (dep - 3)*3 + 3;
        if(dep == 1)    limit = 0;
        else if(dep == 2)   limit = 1;
        int dep33 = dep*dep*dep ;
        for(int i = 0;i <= limit; i++) {
            if(dep33 + i*i > n) break;
            vis[dep33 + i*i] = 1;
        }
        dep++;
    }
}

int dp[55555], a[55555];

int solve(int n) {
    int i, j, tot = 0;
    for(i = 1;i <= n; i++)  if(vis[i])
        a[tot++] = i;
    for(i = 1;i <= n; i++)  dp[i] = INF;
    dp[0] = 0;
    for(i = 0;i < tot; i++) {
        for(j = 0;j <= n; j++) if(j + a[i] <= n) {
            if(dp[j+a[i]] > dp[j] + 1)
                dp[j+a[i]] = dp[j]+1;
        }
    }
    return dp[n];
}

int PlanarGraphShop::bestCount(int n) {
    init(n);
    return solve(n);
}


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