HDU 4339 Query

线段树

#include <cstdio>
#include <cstring>
#include <cstdlib>
#include <algorithm>

#define lson l, m, rt << 1
#define rson m + 1, r, rt << 1 | 1

using namespace std;

const int MAXN = 1000010;

char str1[MAXN];
char str2[MAXN];
bool flag[ MAXN << 2 ];
int len1, len2;

void PushUp( int rt, int l )
{
    int lc = rt << 1;
    int rc = rt << 1 | 1;
    flag[rt] = flag[lc] && flag[rc];
    return;
}

void Update( int L, int num, char c, int l, int r, int rt )
{
    if ( L == l && r == L )
    {
        if ( num == 1 ) str1[L] = c;
        else str2[L] = c;
        if ( str1[L] == str2[L] ) flag[rt] = true;
        else flag[rt] = false;

        return;
    }

    int m = ( l + r ) >> 1;
    if ( L <= m ) Update( L, num, c, lson );
    else Update( L, num, c, rson );

    PushUp( rt, l );
    return;
}

void build( int l, int r, int rt )
{
    if ( l == r )
    {
        if ( str1[l] == str2[l] )
            flag[rt] = true;
        else
            flag[rt] = false;
        return;
    }
    int m = ( l + r ) >> 1;
    build( lson );
    build( rson );
    PushUp( rt, l );
    return;
}

int query( int L, int l, int r, int rt )
{
    if ( flag[rt] )
    {
        return r;
    }
    if ( l == r )
    {
        return r - 1;
    }
    int m = ( l + r ) >> 1;
    if ( L <= m )
    {
        int temp = query( L, lson );
        if ( temp == m ) return query( m + 1, rson );
        else return temp;
    }
    else return query( L, rson );
}

int main()
{
    int T;
    int cas = 0;
    scanf( "%d", &T );
    while ( T-- )
    {
        scanf( "%s", str1 );
        scanf( "%s", str2 );

        len1 = strlen( str1 );
        len2 = strlen( str2 );

        int len = min( len1, len2 );
        build( 0, len - 1, 1 );

        int Q;
        scanf( "%d", &Q );
        printf( "Case %d:\n", ++cas );
        while ( Q-- )
        {
            int op;
            scanf( "%d", &op );
            char st[10];
            if ( op == 1 )
            {
                int a, i;
                scanf( "%d%d%s", &a, &i, st );
                if ( i >= len ) continue;
                Update( i, a, st[0], 0, len - 1, 1 );
            }
            else
            {
                int i;
                scanf( "%d", &i );
                printf( "%d\n", query( i, 0, len - 1, 1 ) - i + 1 );
            }
        }
    }
    return 0;
}