HDU 4339 Query

线段树

  1 #include <cstdio>

  2 #include <cstring>

  3 #include <cstdlib>

  4 #include <algorithm>

  5 

  6 #define lson l, m, rt << 1

  7 #define rson m + 1, r, rt << 1 | 1

  8 

  9 using namespace std;

 10 

 11 const int MAXN = 1000010;

 12 

 13 char str1[MAXN];

 14 char str2[MAXN];

 15 bool flag[ MAXN << 2 ];

 16 int len1, len2;

 17 

 18 void PushUp( int rt, int l )

 19 {

 20     int lc = rt << 1;

 21     int rc = rt << 1 | 1;

 22     flag[rt] = flag[lc] && flag[rc];

 23     return;

 24 }

 25 

 26 void Update( int L, int num, char c, int l, int r, int rt )

 27 {

 28     if ( L == l && r == L )

 29     {

 30         if ( num == 1 ) str1[L] = c;

 31         else str2[L] = c;

 32         if ( str1[L] == str2[L] ) flag[rt] = true;

 33         else flag[rt] = false;

 34 

 35         return;

 36     }

 37 

 38     int m = ( l + r ) >> 1;

 39     if ( L <= m ) Update( L, num, c, lson );

 40     else Update( L, num, c, rson );

 41 

 42     PushUp( rt, l );

 43     return;

 44 }

 45 

 46 void build( int l, int r, int rt )

 47 {

 48     if ( l == r )

 49     {

 50         if ( str1[l] == str2[l] )

 51             flag[rt] = true;

 52         else

 53             flag[rt] = false;

 54         return;

 55     }

 56     int m = ( l + r ) >> 1;

 57     build( lson );

 58     build( rson );

 59     PushUp( rt, l );

 60     return;

 61 }

 62 

 63 int query( int L, int l, int r, int rt )

 64 {

 65     if ( flag[rt] )

 66     {

 67         return r;

 68     }

 69     if ( l == r )

 70     {

 71         return r - 1;

 72     }

 73     int m = ( l + r ) >> 1;

 74     if ( L <= m )

 75     {

 76         int temp = query( L, lson );

 77         if ( temp == m ) return query( m + 1, rson );

 78         else return temp;

 79     }

 80     else return query( L, rson );

 81 }

 82 

 83 int main()

 84 {

 85     int T;

 86     int cas = 0;

 87     scanf( "%d", &T );

 88     while ( T-- )

 89     {

 90         scanf( "%s", str1 );

 91         scanf( "%s", str2 );

 92 

 93         len1 = strlen( str1 );

 94         len2 = strlen( str2 );

 95 

 96         int len = min( len1, len2 );

 97         build( 0, len - 1, 1 );

 98 

 99         int Q;

100         scanf( "%d", &Q );

101         printf( "Case %d:\n", ++cas );

102         while ( Q-- )

103         {

104             int op;

105             scanf( "%d", &op );

106             char st[10];

107             if ( op == 1 )

108             {

109                 int a, i;

110                 scanf( "%d%d%s", &a, &i, st );

111                 if ( i >= len ) continue;

112                 Update( i, a, st[0], 0, len - 1, 1 );

113             }

114             else

115             {

116                 int i;

117                 scanf( "%d", &i );

118                 printf( "%d\n", query( i, 0, len - 1, 1 ) - i + 1 );

119             }

120         }

121     }

122     return 0;

123 }