9月30日机房模拟赛题解

来源：互联网发布：怎么购买捷易通软件编辑：程序博客网时间：2024/05/16 07:49

今天AK啦，而且是rank1，真是超开心，这是弱菜的人生第一次AK

T1并查集，BZOJ 冷战

#include <cstdio>#include <cstring>#include <iostream>#include <algorithm>#include <vector>using namespace std;vector<int> tmp;const int MAXN = 200000 + 10;int n, m, timer, sz[MAXN], fa[MAXN], tim[MAXN], dep[MAXN];struct Un{ int x, y; } U[MAXN];void init( ) { for( register int i = 1; i <= n; i++ ) sz[i] = 1, fa[i] = i; }void Union( int x, int y ) {    while( fa[x] != x ) x = fa[x];    while( fa[y] != y ) y = fa[y];    if( sz[x] > sz[y] ) swap( x, y );    fa[x] = y; tim[x] = ++timer;    sz[y] += sz[x];}void get_dep( int x ) {    if( fa[x] == x ) return;    get_dep( fa[x] );    dep[x] = dep[fa[x]] + 1;}int query( int x, int y ) {    get_dep(x); get_dep(y);    int tmp = 0;    if( dep[x] < dep[y] ) swap( x, y );    while( dep[x] > dep[y] && x != y ) tmp = max( tmp, tim[x] ), x = fa[x];    while( x != y ) { tmp = max( tmp, max( tim[x], tim[y] ) ); x = fa[x]; y = fa[y]; }    return tmp;}int main( ) {    freopen( "union.in", "r", stdin );    freopen( "union.out", "w", stdout );    scanf( "%d%d", &n, &m );    init( ); int x, y;    for( register int i = 1; i <= n - 1; i++ ) {        scanf( "%d%d", &U[i].x, &U[i].y ); tmp.push_back( U[i].x ); tmp.push_back( U[i].y );    }    tmp.erase( unique( tmp.begin(), tmp.end() ), tmp.end() );    for( register int i = 1; i <= n - 1; i++ ) {        U[i].x = lower_bound( tmp.begin(), tmp.end(), U[i].x ) - tmp.begin() + 1 ;        U[i].y = lower_bound( tmp.begin(), tmp.end(), U[i].y ) - tmp.begin() + 1 ;    }    for( register int i = 1; i <= n - 1; i++ ) {        Union( U[i].x, U[i].y );    }    for( register int i = 1; i <= m; i++ ) {        scanf( "%d%d", &x, &y );        printf( "%d\n", query( x, y ) );     }    return 0;}

T2 LCS转LIS

#include <iostream>#include <cstring>#include <cstdio>using namespace std;const int MAXN = 100000 + 10;const int inf = 2147483647;int n, ans, a[MAXN], arc[MAXN], b[MAXN], g[MAXN], f[MAXN]; int main( ) {    freopen( "lcs.in", "r", stdin );    freopen( "lcs.out", "w", stdout );    scanf( "%d", &n );    for( register int i = 1; i <= n; i++ ) scanf( "%d", &a[i] ), arc[a[i]] = i;    for( register int i = 1; i <= n; i++ ) scanf( "%d", &b[i] ), b[i] = arc[b[i]];    for( register int i = 1; i <= n; i++ ) g[i] = inf;    int ans = 0;    for( register int i = 1; i <= n; i++ ) {        int k = lower_bound( g + 1, g + n + 1, b[i] ) - g;        f[i] = k;        g[k] = b[i];        ans = max( ans, f[i] );    }    printf( "%d\n", ans );    return 0;}//g[i]表示最长上升子序列长度为i时,最小满足的值为g[i],也就是说最大的那个值为g[i]//比如 1,3,5,7, 则 g[4] = 7, g[2] = 3;//由于对于一个决策而言,如果g的数组下标相同,选取最小的值最好,因此我们每次用最小的值去更新//故g函数为单调递增函数,所以动态修改g函数,g函数的值g[k]应该赋成最新的b[i],其中k为g中的第几位

T3 大模拟

#include <cstdio>#include <cstring>#include <algorithm>#include <iostream>#include <vector>using namespace std;const int MAXN = 1000;struct Name { string nm; }name[MAXN];int cnt = 0, Q, fa[MAXN], still[MAXN],is_files[MAXN];vector <int> son[MAXN];int main( ) {    freopen( "files.in", "r", stdin );    freopen( "files.out", "w", stdout );    scanf( "%d", &Q ); int pointer = 0;    while( Q-- ) { string opt, Opt_Name;        cin >> opt;        if( opt != "ls" ) cin >> Opt_Name;        if( opt == "cd" ) {            if( Opt_Name == ".." ) {                if( pointer != 0 ) pointer = fa[pointer];                else printf( "No parent directory!\n" );            } else { bool judge = true;                for( register int i = 0; i < son[pointer].size(); i++ ) {                    int ss = son[pointer][i];                    if( name[ss].nm == Opt_Name && still[ss] && is_files[ss] ) {                        pointer = ss;                        judge = false;                        break;                    }                }                if( judge ) printf( "No such directory!\n" );            }        } else if( opt == "touch" ) {            bool judge = true;            for( register int i = 0; i < son[pointer].size(); i++ ) {                int ss = son[pointer][i];                if( name[ss].nm == Opt_Name && still[ss] && is_files[ss] == 0 ) {                    printf( "File already exists!\n" );                    judge = false; break;                }            }            if( judge ) {                cnt++;                fa[cnt] = pointer;                son[pointer].push_back(cnt);                name[cnt].nm = Opt_Name;                still[cnt] = 1;            }        } else if( opt == "rm" ) {            bool judge = true;            for( register int i = 0; i < son[pointer].size(); i++ ) {                int ss = son[pointer][i];                if( name[ss].nm == Opt_Name && still[ss] && is_files[ss] == 0 ) {                    still[ss] = 0; judge = false; break;                }             }            if( judge ) { printf( "No such file!\n" ); }        } else if( opt == "mkdir" ) {            bool judge = true;            for( register int i = 0; i < son[pointer].size(); i++ ) {                int ss = son[pointer][i];                if( name[ss].nm == Opt_Name && still[ss] && is_files[ss] ) {                    printf( "Directory already exists!\n"); judge = false; break;                }             }            if( judge ) {                cnt++;                fa[cnt] = pointer;                son[pointer].push_back(cnt);                is_files[cnt] = 1;                still[cnt] = 1;                name[cnt].nm = Opt_Name;            }        } else if( opt == "rmdir" ) {            bool judge = true;            for( register int i = 0; i < son[pointer].size(); i++ ) {                int ss = son[pointer][i];                if( name[ss].nm == Opt_Name && still[ss] && is_files[ss] ) {                    still[ss] = 0; judge = false; break;                }             }            if( judge ) { printf( "No such directory!\n" ); }        } else if( opt == "ls" ) {             for( register int i = 0; i < son[pointer].size(); i++ ) {                int ss = son[pointer][i];                if( still[ss] ) {                    if( is_files[ss] ) cout << name[ss].nm << ' ' << "<D>" << endl;                     else               cout << name[ss].nm << ' ' << "<F>" << endl;                }            }        }    }    return 0;}/*3mkdir standytouch totalfrankls6mkdir standycd standytouch totalfrankcd ..rm totalfrankls*/

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