]]>
鍦℉DOJ涓婄粍闃熷仛鏉窞璧涚殑棰樼殑鏃跺欑籂緇撲簡鍗婂ぉ涔熸病榪囥傘傝禌鍚庡惉璇存濊礬灝辨槸KMP錛孌P錛屾垜鐘舵佽漿縐誨鐞嗘湁闂銆傘?br> 浠婂ぉ鍙堟悶浜嗕竴鏅氫笂錛岃鏁橺iroy澶х墰涔嬪悗鍙戠幇閿欒鍘熷洜鍦╯鐘舵佷笉鐢ㄥ鐞?br>鎬濊礬錛歞p杞Щ鏂圭▼寰堝ソ鎯籌紝dp[i][j]琛ㄧず宸茬粡鎸変簡i嬈★紝褰撳墠鐘舵佹槸j(S鐨勭j涓瓧姣?錛屾鐜囨槸澶氬皯
鍏蜂綋瀹炵幇榪囩▼瑙佷唬鐮佸強娉ㄩ噴
//Problem: HDOJ 3689//Source: 2010 Hangzhou Regional On-Site J Infinite monkey theorem//Solution: KMP+DP(like DFA)//Status: Accepted//Running Time: 15Ms//Author: Uriel//2010.10.29#include<stdio.h>#include<string.h>double dp[1050][20],dd[20];char st[30],ch[30];double p[30];int nxt[30],s;
void GetNext(char* str)
{
nxt[0]=-1; int i=0,j=-1;
while(str[i]){ if(j==-1 || str[i]==str[j]){ i++; j++; nxt[i]=j;
} else j=nxt[j]; }
}int main(){ int n,m; int i,j,k; while(scanf("%d %d",&n,&m),n|m){ for(i=0;i<n;i++){ scanf("%s",st); ch[i]=st[0]; scanf("%lf",&p[i]); } scanf("%s",st); for(i=0;i<=m;++i){ for(j=0;j<=s;++j)dp[i][j]=0.0; } s=strlen(st); GetNext(st); dp[0][0]=1.0; for(i=1;i<=m;i++){ //鍏辨寜m嬈?/span> for(j=0;j<s;j++){ //鏋氫婦褰撳墠鐘舵?涓嶇敤鑰冭檻j=s,鍥犱負榪欐椂宸茬粡婊¤凍瑕佹眰,涓嶇敤綆椾笅鍘?! for(k=0;k<n;++k){ //鏋氫婦褰撳墠榪欐鎸夊摢涓敭 if(!j){ //濡傛灉褰撳墠鐘舵佹槸榪樻病鏈夋寜鍑烘紜覆鐨勫墠緙 if(ch[k]==st[0])dp[i][1]+=dp[i-1][0]*p[k]; //濡傛灉榪欐鎸夌殑鏄窛鐨勭涓涓瓧姣?鐘舵佷粠0鍙樹負1 else //鍚﹀垯0鐘舵佺殑姒傜巼绱姞 dp[i][0]+=dp[i-1][0]*p[k]; } else if(ch[k]==st[j]){ //濡傛灉褰撳墠鎸夊浜嗚涓插綋鍓嶇姸鎬佺殑鍚庝竴涓瓧姣?/span> dp[i][j+1]+=dp[i-1][j]*p[k]; //鐘舵?1 } else{ int tp=j; while(tp>-1 && ch[k]!=st[tp])tp=nxt[tp]; //鍒╃敤KMP鐨凬ext鍑芥暟褰撳墠鐘舵佽綆楁寜涓媖涔嬪悗鐨勭姸鎬?鑳藉尮閰嶇殑鍓嶇紑闀垮害) if(tp==-1)dp[i][0]+=dp[i-1][j]*p[k]; //濡傛灉褰撳墠鍖歸厤澶辮觸,鐘舵佸彉涓?錛屼笖绱姞鐘舵?鐨勬鐜?/span> else //鍚﹀垯鐘舵佷負tp+1,鐘舵乼p+1鐨勬鐜囩瘡鍔?/span> dp[i][tp+1]+=dp[i-1][j]*p[k]; } } } } double ans=0.0; for(i=1;i<=m;++i)ans+=dp[i][s];//鎵鏈夐暱搴﹁兘寰楀埌鐘舵乻鐨勬鐜囦箣鍜屽嵆涓烘墍姹?/span> printf("%.2f%%\n",100*ans); } return 0;}榪欎箞澶ф按鐨勯鎼炰簡榪欎箞涔呫傘傝屼笖瀛楃涓插張鏄垜鐨勪換鍔°傘傛澂鍏楓傘?br> 涓嬪懆涓夊幓鎴愰兘錛?9h45min錛岀涓嬈″潗榪欎箞闀挎椂闂寸伀杞︺傘?br> 紲堢シDSW Chengdu Regional 濂借繍銆傘俁egional鏄姝ょ殑瀹濊吹銆傘備笉鐭ラ亾浠ュ悗榪樻湁娌℃湁鏈轟細銆傘?
]]>