79 lines
2.3 KiB
C++
79 lines
2.3 KiB
C++
#include<stdio.h>
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#include<iostream>
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#include<map>
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#include<algorithm>
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#include<string.h>
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#include<stdlib.h>
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#define MAXN 1005
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using namespace std;
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double dp[55][MAXN], cost[MAXN][MAXN];
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map<int ,double> has;
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struct Info{
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double pos;
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double p;
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}info[MAXN];
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int main()
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{
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int N, M, i, n, a, j, k, pos;
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double l, r, suml, sumr;
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double b, min, temp, t;
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while(scanf("%d%d",&N, &M)&&(N + M))
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{
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has.clear();
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for( i = 1; i <= N; ++ i )
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{
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scanf("%d", &n);++n;
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while(--n)
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{
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scanf("%d%lf", &a, &b);
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has[a]+=b;
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}
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}
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N = 0;
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for(map<int, double>::iterator it = has.begin(); it != has.end(); ++it)
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{
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info[++N].pos = it->first;
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info[N].p = it->second;
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}
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for(j = N; j >= 1; j--)
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{
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pos = j;
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cost[j][j] = 0;
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l = r = suml = 0;
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sumr = info[j].p;
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for(k = j-1; k >= 1; --k )
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{
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suml += info[k].p;
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l += (info[pos].pos-info[k].pos) * info[k].p;
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temp = l + r;
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while((pos > 1)&&(temp>(t = (l + r + (sumr - suml) * (info[pos].pos - info[pos - 1].pos)))))
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{
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l -= suml * (info[pos].pos - info[pos - 1].pos);
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r += sumr * (info[pos].pos - info[pos - 1].pos);
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--pos;
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suml -= info[pos].p;
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sumr +=info[pos].p;
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temp = t;
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}
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cost[k][j] = temp;
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}
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}
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for(i = 1; i <= N; i++)dp[0][i] = 1e300;
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for(i = 0; i <= M; i++)dp[i][0] = 0;
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for(i = 1; i <= M; i++)
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{
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for(j = N; j >= 1; j--)
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{
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min = dp[i-1][j-1] + cost[j][j];
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for(k = j-1; k >= 1; --k )
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{
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if(dp[i - 1][k - 1] + cost[k][j] < min)min = dp[i - 1][k - 1] + cost[k][j];
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}
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dp[i][j] = min;
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}
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}
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printf("%0.2lf\n",dp[M][N]);
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}
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return 0;
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}
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