Hihocoder #1300: Carp flag DP at the exhibition resort

Topic Links:

http://hihocoder.com/problemset/problem/1300

Exercises

Use the stack to preprocess each ') ' matched ' (' seat, placed in the POS array.

Dp[i] Indicates the number of valid substrings ending with I, then the transfer equation is easy to know:

dp[i]=dp[pos[i]-1]+1;

Code:

#include <iostream>#include<cstdio>#include<stack>using namespaceStd;typedefLong LongLL;Const intMAXN = 1e6 +Ten;CharSTR[MAXN]; LL DP[MAXN];intPOS[MAXN];voidinit () {memset (pos,0,sizeof(POS)); Memset (DP,0,sizeof(DP));}intMain () { while(SCANF ("%s", str +1) ==1) {        intlen = strlen (str +1);        Init (); Stack<int>MS;  for(inti =1; I <= Len; i++) {            if(Str[i] = ='(') {Ms.push (i); }            Else {                if(!Ms.empty ()) {                    intj =ms.top (); Ms.pop (); Pos[i]=J; }}} LL ans=0;  for(inti =1; I <= Len; i++) {            if(pos[i]>=1) Dp[i] = dp[pos[i]-1] +1; Ans+=Dp[i]; } printf ("%lld\n", ans); }    return 0;}

Hihocoder #1300: Carp flag DP at the exhibition resort