[51NOD1272]最大距离（贪心）

题目链接：http://www.51nod.com/onlineJudge/questionCode.html#!problemId=1272

思路：排序后由于序列都是顺序的，则只需要考虑序号了，加入当前维护的序号比后面的小，则更新ret。否则更新当前序号

#include <algorithm>
#include <iostream>
#include <iomanip>
#include <cstring>
#include <climits>
#include <complex>
#include <fstream>
#include <cassert>
#include <cstdio>
#include <bitset>
#include <vector>
#include <deque>
#include <queue>
#include <stack>
#include <ctime>
#include <set>
#include <map>
#include <cmath>

using namespace std;
#define fr first
#define sc second
#define cl clear
#define BUG puts("here!!!")
#define W(a) while(a--)
#define pb(a) push_back(a)
#define Rint(a) scanf("%d", &a)
#define Rll(a) scanf("%lld", &a)
#define Rs(a) scanf("%s", a)
#define Cin(a) cin >> a
#define FRead() freopen("in", "r", stdin)
#define FWrite() freopen("out", "w", stdout)
#define Rep(i, len) for(int i = 0; i < (len); i++)
#define For(i, a, len) for(int i = (a); i < (len); i++)
#define Cls(a) memset((a), 0, sizeof(a))
#define Clr(a, p) memset((a), (p), sizeof(a))
#define Full(a) memset((a), 0x7f7f7f, sizeof(a))
#define lrt rt << 1
#define rrt rt << 1 | 1
#define pi 3.14159265359
#define RT return
#define lowbit(p) p & (-p)
#define onenum(p) __builtin_popcount(p)
typedef long long LL;
typedef long double LD;
typedef unsigned long long ULL;
typedef pair<int, int> pii;
typedef pair<string, int> psi;
typedef pair<LL, LL> pll;
typedef map<string, int> msi;
typedef vector<int> vi;
typedef vector<LL> vl;
typedef vector<vl> vvl;
typedef vector<bool> vb;

const int maxn = 50500;
typedef struct Node {
    int i, n;
}Node;

int n;
int a[maxn];
Node b[maxn];

bool cmp(Node x, Node y) {
    if(x.n == y.n) return x.i < y.i;
    return x.n < y.n;
}

int main() {
    // FRead();
    while(~Rint(n)) {
        Rep(i, n) {
            Rint(a[i]);
            b[i].n = a[i]; b[i].i = i;
        }
        sort(b, b+n, cmp);
        int ret = 0, cur = b[0].i;
        For(i, 1, n) {
            if(b[i].i > cur) ret = max(ret, b[i].i-cur);
            else cur = b[i].i;
        }
        printf("%d
", ret);
    }
    RT 0;
}