【HDOJ】4261 Estimation

挺不错的一道题，基本思路是dp。关键点是如何求区间内的Sigma|A_i-B_i|。
线段树做TLE了，优先队列可以过。

 /* 4261 */
 #include <iostream>
 #include <sstream>
 #include <string>
 #include <map>
 #include <queue>
 #include <set>
 #include <stack>
 #include <vector>
 #include <deque>
 #include <algorithm>
 #include <cstdio>
 #include <cmath>
 #include <ctime>
 #include <cstring>
 #include <climits>
 #include <cctype>
 #include <cassert>
 #include <functional>
 #include <iterator>
 #include <iomanip>
 using namespace std;
 //#pragma comment(linker,"/STACK:102400000,1024000")

 #define sti                set<int>
 #define stpii            set<pair<int, int> >
 #define mpii            map<int,int>
 #define vi                vector<int>
 #define pii                pair<int,int>
 #define vpii            vector<pair<int,int> >
 #define rep(i, a, n)     for (int i=a;i<n;++i)
 #define per(i, a, n)     for (int i=n-1;i>=a;--i)
 #define clr                clear
 #define pb                 push_back
 #define mp                 make_pair
 #define fir                first
 #define sec                second
 #define all(x)             (x).begin(),(x).end()
 #define SZ(x)             ((int)(x).size())
 #define lson            l, mid, rt<<1
 #define rson            mid+1, r, rt<<1|1

 const int INF = 1e9;
 const int maxn = ;
 const int maxm = ;
 int n, m;
 int a[maxn];
 int dp[maxm][maxn];
 int dif[maxn][maxn];

 void solve() {
     int tmp;

     rep(i, , n+) {
         priority_queue<int> q;
         priority_queue<int, vi, greater<int> > Q;

         int ls, rs;
         int ln, rn;
         int x, xx;
         int l = ;

         ln = rn = ;
         ls = rs = ;
         rep(j, i, n+) {
             ++l;
             x = a[j];
             if (l & ) {
                 ++ln;
                 if (rn && Q.top()<x) {
                     xx = Q.top();
                     Q.pop();
                     q.push(xx);
                     ls += xx;
                     Q.push(x);
                     rs += x - xx;
                 } else {
                     q.push(x);
                     ls += x;
                 }

                 x = q.top();
                 tmp = rs - ls + x;
                 dif[i][j] = tmp;
             } else {
                 ++rn;
                 if (q.top() > x) {
                     xx = q.top();
                     q.pop();
                     Q.push(xx);
                     rs += xx;
                     q.push(x);
                     ls += x - xx;
                 } else {
                     Q.push(x);
                     rs += x;
                 }

                 x = q.top();
                 tmp = rs - ls;
                 dif[i][j] = tmp;
             }
         }
     }

     rep(j, , n+) {
         dp[][j] = dif[][j];
     }

     rep(i, , m+) {
         rep(j, i, n+) {
             dp[i][j] = INF;
             rep(k, i-, j) {
                 dp[i][j] = min(dp[i][j], dp[i-][k]+dif[k+][j]);
             }
         }
     }

     printf("%d\n", dp[m][n]);
 }

 int main() {
     ios::sync_with_stdio(false);
     #ifndef ONLINE_JUDGE
         freopen("data.in", "r", stdin);
         freopen("data.out", "w", stdout);
     #endif

     while (scanf("%d %d", &n, &m)!=EOF && (n||m)) {
         rep(i, , n+) {
             scanf("%d", &a[i]);
         }
         solve();
     }

     #ifndef ONLINE_JUDGE
         printf("time = %d.\n", (int)clock());
     #endif

     return ;
 }

数据生成器。

 from random import randint, shuffle
 import shutil
 import string

 def GenDataIn():
     with open("data.in", "w") as fout:
         t =
         bound = **
         for tt in xrange(t):
             n = randint(, )
             k = randint(, )
             fout.write("%d %d\n" % (n, k))
             dataList = []
             for i in xrange(n):
                 x = randint(-bound, bound)
                 dataList.append(x)
             fout.write(" ".join(map(str, dataList)) + "\n")
         fout.write("0 0\n")        

 def MovDataIn():
     desFileName = "F:\eclipse_prj\workspace\hdoj\data.in"
     shutil.copyfile("data.in", desFileName)

 if __name__ == "__main__":
     GenDataIn()
     MovDataIn()