Zoj3469 food delivery interval DP

A fast food restaurant delivers food. Now N families make orders by phone.V-1But every family has an unhappy value, which doubles every minute. To a certain extent, the family will no longer order takeout, now, in order to have more family orders in the future, the sum of unhappy values of all users should be minimized when takeout is sent.

Train of Thought: interval DP

DP [I] [J] [0]: indicates the minimum value in the range from I to J and remains at the I point.

DP [I] [J] [1]: indicates the minimum value in the range from I to J and remains at the J point.

The transfer equation is

Sum [I] indicates the sum of 1 to I. When I to J is enumerated, the intervals (0, I) and (J, n) must be doubled.

DP [I] [J] [0] = min (DP [I] [J] [0], DP [I + 1] [J] [0] + (sum [I] + sum [N]-sum [J]) * (p [I + 1]. x-P [I]. x ));
DP [I] [J] [0] = min (DP [I] [J] [0], DP [I + 1] [J] [1] + (sum [I] + sum [N]-sum [J]) * (p [J]. x-P [I]. x ));

DP [I] [J] [1] = min (DP [I] [J] [1], DP [I] [J-1] [0] + (sum [I-1] + sum [N]-sum [J-1]) * (p [J]. x-P [I]. x ));
DP [I] [J] [1] = min (DP [I] [J] [1], DP [I] [J-1] [1] + (sum [I-1] + sum [N]-sum [J-1]) * (p [J]. x-P [J-1]. x ));

1 // # pragma comment (linker, "/Stack: 167772160") // manually expand the stack ~~~~ HDU uses C ++ to submit 2 # include <cstdio> 3 # include <cstring> 4 # include <cstdlib> 5 # include <iostream> 6 # include <queue> 7 # include <stack> 8 # include <cmath> 9 # include <set> 10 # include <algorithm> 11 # include <vector> 12 # include <map> 13 // # include <malloc. h> 14 using namespace STD; 15 # define CLC (a, B) memset (a, B, sizeof (a) 16 # define ll long long17 const int INF = 0x3f3f3f3f; 18 const double EPS = 1e-5; 19 // Const double Pi = ACOs (-1); 20 const ll mod = 9901; 21 const int n = 1010; 22 23 // inline int R () {24 // int x = 0, F = 1; char CH = getchar (); 25 // while (CH> '9' | ch <'0 ') {If (CH = '-') F =-1; CH = getchar ();} 26 // while (CH> = '0' & Ch <= '9') {x = x * 10 + CH-'0'; CH = getchar ();} 27 // return x * F; 28 //} 29 struct node {30 int X, Y; 31} p [N]; 32 33 34 bool CMP (node, node B) {35 return. x <B. x; 36} 37 38 int DP [N] [N] [2]; 39 int sum [N]; 4 0 41 int main () {42 int N, V, X; 43 while (~ Scanf ("% d", & N, & V, & X) {44 for (INT I = 1; I <= N; I ++) {45 scanf ("% d", & P [I]. x, & P [I]. y); 46} 47 P [++ N]. X = x; 48 p [N]. y = 0; 49 sort (p + 1, p + 1 + N, CMP); 50 51 sum [0] = 0; 52 for (INT I = 1; I <= N; I ++) {53 sum [I] = sum [I-1] + P [I]. y; 54} 55 int TEM; 56 for (INT I = 1; I <= N; I ++) {57 if (P [I]. X = x) {58 TEM = I; 59 break; 60} 61} 62 63 for (INT I = 0; I <= N; I ++) {64 for (Int J = 0; j <= N; j ++) {65 DP [I] [J] [0] = DP [I] [J] [1] = inf; 66} 67} 68 DP [TEM] [TEM] [1] = DP [TEM] [TEM] [0] = 0; 69 70 for (INT I = TEM; i> = 1; I --) {71 for (Int J = TEM; j <= N; j ++) {72 if (I = J) continue; 73 74 DP [I] [J] [0] = min (DP [I] [J] [0], DP [I + 1] [J] [0] + (sum [I] + sum [N]-sum [J]) * (p [I + 1]. x-P [I]. x); 75 DP [I] [J] [0] = min (DP [I] [J] [0], DP [I + 1] [J] [1] + (sum [I] + sum [N]-sum [J]) * (p [J]. x-P [I]. x); 76 77 DP [I] [J] [1] = min (DP [I] [J] [1], DP [I] [J-1] [0] + (sum [I-1] + sum [N]-sum [J-1]) * (p [J]. x-P [I]. x); 78 DP [I] [J] [1] = min (DP [I] [J] [1], DP [I] [J-1] [1] + (sum [I-1] + sum [N]-sum [J-1]) * (p [J]. x-P [J-1]. x); 79} 80} 81 printf ("% d \ n", V * min (DP [1] [N] [0], DP [1] [N] [1]); 82} 83 return 0; 84}

 

Zoj3469 food delivery interval DP