BZOJ 1113: [Poi2008]海报PLA

1113: [Poi2008]海报PLA

Time Limit: 10 Sec  Memory Limit: 162 MB
Submit: 1025  Solved: 679
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Description

N个矩形,排成一排. 现在希望用尽量少的矩形海报Cover住它们.

Input

第一行给出数字N,代表有N个矩形.N在[1,250000] 下面N行,每行给出矩形的长与宽.其值在[1,1000000000]2 1/2 Postering

Output

最少数量的海报数.

Sample Input

5
1 2
1 3
2 2
2 5
1 4

Sample Output

4

HINT

 

Source

 

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分析

单调栈

代码

/*<--- Opinion --->*/

   #define HEADER
   #define MYMATH
// #define FILEIO
// #define FSTREAM
// #define FREOPEN
   #define FASTREAD
   #define SHORTNAME

///// HEADER FILE /////

#ifdef HEADER

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

#include <sstream>
#include <fstream>
#include <iostream>

#include <set>
#include <map>
#include <list>
#include <queue>
#include <stack>
#include <vector>
#include <utility>
#include <functional>

#endif

///// SHORTNAME /////

#ifdef SHORTNAME

#define LL long long
#define ll long long
#define re register
#define un unsigned
#define rb re bool
#define ri re int
#define ui un int
#define rl re LL
#define ul un LL

#define rep (x, y) for (ri i = x; i <= y; ++i)
#define repi(x, y) for (ri i = x; i <= y; ++i)
#define repj(x, y) for (ri j = x; j <= y; ++j)
#define repk(x, y) for (ri k = x; k <= y; ++k)

#define upto(x) for (ri i = 1; i <= x; ++i)
#define dnto(x) for (ri i = x; i >= 1; --i)

#define up(x) for (ri i = 1; i <= x; ++i)
#define dn(x) for (ri i = x; i >= 1; --i)

#define put(x)   printf("%lld ",  (LL)x)
#define putln(x) printf("%lld
", (LL)x)

#endif

///// FASTREAD /////

#ifdef FASTREAD

const int FR_lim = 10000000;

char *FR_c;

inline void fsetup(FILE *FR_file)
{
    FR_c = new char[FR_lim];
    fread(FR_c, 1, FR_lim, FR_file);
}

template <class T>
inline void fread(T &FR_num)
{
    FR_num = 0; rb FR_neg = 0;

    while (*FR_c < '0')
        if (*FR_c++ == '-')
            FR_neg ^= true;

    while (*FR_c >= '0')
        FR_num = FR_num*10 + *FR_c++ - '0';

    if(FR_neg)FR_num = -FR_num;
}

#endif

///// FILE I/O /////

#ifdef FILEIO

FILE *FIN = fopen("input.txt", "r");
FILE *FOUT = fopen("output.txt", "w");

#ifndef FSTREAM

#define fin FIN
#define fout FOUT

#endif

#endif

///// FSTREAM /////

#ifdef FSTREAM

std::ifstream fin("input.txt");
std::ofstream fout("output.txt");

#endif

///// MYMATH /////

#ifdef MYMATH

#define min(a, b) (a < b ? a : b)
#define max(a, b) (a > b ? a : b)

#define Min(a, b) a = min(a, b)
#define Max(a, b) a = max(a, b)

#define abs(x) (x < 0 ? -x : x)

#define sqr(x) ((x)*(x))

#endif

///// _MAIN_ /////

void _main_(void);

signed main(void)
{

#ifdef FREOPEN
    freopen("input.txt", "r", stdin);
    freopen("output.txt", "w", stdout);
#endif

    _main_();

#ifdef FILEIO
    fclose(FIN);
    fclose(FOUT);
#endif

#ifdef FREOPEN
    fclose(stdin);
    fclose(stdout);
#endif

#ifdef FSTREAM
    fin.close();
    fout.close();
#endif

    return 0;
}

/*<--- Main --->*/

#define N 250005

int n;
int ans;
int h[N];
int stk[N];
int tot = 0;

void _main_(void)
{
    fsetup(stdin);
    
    fread(n);
    
    ri x;
    
    up(n)
    {
        fread(x); fread(x);
        while (tot && stk[tot] > x)--tot;
        if (tot && stk[tot] == x)++ans;
        stk[++tot] = x;
    }
    
    putln(n - ans);
}

好像那天特别高兴的样子，不知不觉就敲了个不明所以的模板， 补一份正常的代码。

#include <bits/stdc++.h>
signed main(void) {
    int n, tot = 0;
    scanf("%d", &n);
    std::stack<int> stk;
    for (int i = 1; i <= n; ++i) {
        int h; scanf("%*d%d", &h);
        while (!stk.empty() && h < stk.top())
            stk.pop();
        if (!stk.empty() && h == stk.top())
            ++tot;
        stk.push(h);
    }
    printf("%d
", n - tot);
}

@Author: YouSiki