"NOIP 2004" Insect Food Calculation

Because the machine room is broken network state, the school's small v evaluation of the total display unaccept, so in the afternoon after school and Xiaoyimi evening home study, to do this problem.

Search + Pruning Optimization:

At first I was down to the high-level fill number, so violent on the Vijos have 90 points, if Noip can get so many points I also willingly write this violence

#include <cstdio> #include <cstring> #include <algorithm>using namespace Std;int s1[27], s2[27], an[27 ], ans[27], N;bool vis[27], PD = 0;inline void dfs1 (int, int), inline void dfs3 (int tmp, int delta) {int c = an[tmp];if (an  S[C] = =-1) {int num = (ans[s1[tmp]] + ans[s2[tmp]] + delta), MO = num% n;if (!vis[mo]) {Vis[mo] = 1;ans[c] = MO;DFS1 (tmp + 1, num/n); if (PD) RETURN;VIS[MO] = 0;ans[c] =-1;}} else {int num = (ans[s1[tmp]] + ans[s2[tmp]] + delta), if (ans[c] = = num% n) DFS1 (tmp + 1, num/n), if (PD) return;;}  inline void dfs2 (int tmp, int delta) {int c = s2[tmp];if (ans[c] = =-1) {for (int i = 0; i < n; ++i) if (!vis[i]) {Vis[i] = 1;ans[c] = I;DFS3 (tmp, Delta), if (PD) return;vis[i] = 0;ans[c] =-1;}} else {DFS3 (tmp, delta); if (PD) return;}} inline void dfs1 (int tmp, int delta) {if (tmp > N) {if (delta = = 0) PD = 1;return;} int c = s1[tmp];if (ans[c] = = 1) {for (int i = 0; i < n; ++i) if (!vis[i]) {vis[i] = 1;ans[c] = I;DFS2 (tmp, delta); if (p d) Return;vis[i] = 0;ans[c] =-1;}} else {DFS2 (tmp, delta); if (PD) return;}} int main () {scanf ("%d\n", &n), char c;for (int i = n; i > 0; i) {c = GetChar (); s1[i] = C-' A ';} scanf ("\ n"); for (int i = n; i > 0; i) {c = GetChar (); s2[i] = C-' A ';} scanf ("\ n"); for (int i = n; i > 0; i) {c = GetChar (); an[i] = C-' A ';} for (int i = 0; i < n; ++i) ans[i] = -1;DFS1 (1, 0); for (int i = 0; i < n; ++i) printf ("%d", ans[i]); return 0;}

Positive solution: First sweep out the order of the letters appear, in this sweep out of the sequence of violence, after each violence simply sweep the whole equation to $check$, this is the only and most important I write the pruning, can get rid of the group of T-off data:

Input

-
nlhfieasbrqjogkmdpct
NQGPSIIGKDMFDCBFMQSO
Pnkntolheijhfgjkhjgg

Output

0 9 (7) 1 4 2 8 5 one 3 6

AC Code:

#include <cstdio> #include <cstring> #include <algorithm>using namespace Std;int s1[27], s2[27], an[27 ], ans[27], N, tb[27], TN = 0;bool vis[27], pan = 0;inline void mktb (int x) {if (!vis[x]) {vis[x] = 1;tb[++tn] = x;}} inline bool PD () {bool p = 0;int Delta = 0;for (int i = 1; I <= n; ++i) {int a = Ans[s1[i]], B = ans[s2[i]], C = ans[an[i ]];if (A = =-1 | | b = = 1) {p = 1;} else {if (c = = 1) {if (p) {if (a + b = = n-1) p = 1;elsep = 0, Delta = (A + b)/n;} el SE {p = 0;delta = (A + b + delta)/n;}}  else {if (p) {if ((A + b)% n = = c) {p = 0;delta = (A + b)/n;} else if ((A + B + 1)% n = = c) {p = 0;delta = (A + B + 1) /n;} Elsereturn 1;} else {if ((A + B + Delta)% n! = c) return 1;else {p = 0;delta = (A + b + delta)/n;}}}} if (!p && delta = = 1) return 1;elsereturn 0;} inline void dfs (int tmp) {if (PD ())) return;if (tmp > N) {pan = 1;return;}  for (int i = 0; i < n; ++i) if (!vis[i]) {vis[i] = 1;ans[tb[tmp]] = I;DFS (tmp + 1); if (pan) return;vis[i] = 0;ans[tb[tmp]] =-1;}} int main () {scanf ("%d\n", &n), char c;for (int i = n; i > 0; i) {c = GetChar (); s1[i] = C-' A ';} scanf ("\ n"); for (int i = n; i > 0; i) {c = GetChar (); s2[i] = C-' A ';} scanf ("\ n"); for (int i = n; i > 0; i) {c = GetChar (); an[i] = C-' A ';} for (int i = 1; I <= n; ++i) {MKTB (s1[i]); MKTB (S2[i]); MKTB (An[i]);} for (int i = 0; i < n; ++i) Vis[i] = 0, ans[i] = -1;dfs (1); for (int i = 0; i < n; ++i) printf ("%d", ans[i]); return 0;}

No,,,, XyX and I played a game of the Board of the afternoon, SG What's really not ah, the provincial election to explode 0 TWT

"NOIP 2004" Insect Food Calculation