UVA 514 Rails

栈模拟一下，看看输入的顺序能否由正整数序列得到。数组模拟栈或用stl都可以。

如果当前数字比栈顶大，就把之间没用过的都压进栈里，小就return 0，相等就弹栈。#include<algorithm>
#include<iostream>
#include<cstring>
#include<cstdio>
#include<vector>
#include<string>
#include<queue>
#include<cmath>
#include<set>
///LOOP
#define REP(i, n) for(int i = 0; i < n; i++)
#define FF(i, a, b) for(int i = a; i < b; i++)
#define FFF(i, a, b) for(int i = a; i <= b; i++)
#define FD(i, a, b) for(int i = a - 1; i >= b; i--)
#define FDD(i, a, b) for(int i = a; i >= b; i--)
///INPUT
#define RI(n) scanf("%d", &n)
#define RII(n, m) scanf("%d%d", &n, &m)
#define RIII(n, m, k) scanf("%d%d%d", &n, &m, &k)
#define RIV(n, m, k, p) scanf("%d%d%d%d", &n, &m, &k, &p)
#define RV(n, m, k, p, q) scanf("%d%d%d%d%d", &n, &m, &k, &p, &q)
#define RFI(n) scanf("%lf", &n)
#define RFII(n, m) scanf("%lf%lf", &n, &m)
#define RFIII(n, m, k) scanf("%lf%lf%lf", &n, &m, &k)
#define RFIV(n, m, k, p) scanf("%lf%lf%lf%lf", &n, &m, &k, &p)
#define RS(s) scanf("%s", s)
///OUTPUT
#define PN printf("\n")
#define PI(n) printf("%d\n", n)
#define PIS(n) printf("%d ", n)
#define PS(s) printf("%s\n", s)
#define PSS(s) printf("%s ", n)
///OTHER
#define PB(x) push_back(x)
#define CLR(a, b) memset(a, b, sizeof(a))
#define CPY(a, b) memcpy(a, b, sizeof(b))
#define display(A, n, m) {REP(i, n){REP(j, m)PIS(A[i][j]);PN;}}

using namespace std;
typedef long long LL;
typedef pair<int, int> P;
const int MOD = 100000000;
const int INFI = 1e9 * 2;
const LL LINFI = 1e17;
const double eps = 1e-6;
const double pi = acos(-1.0);
const int N = 1111;
const int M = 22;
const int move[8][2] = {0, 1, 0, -1, 1, 0, -1, 0, 1, 1, 1, -1, -1, 1, -1, -1};

int a
, s
, n, sp;
bool vis
;

bool check()
{
int m = 1;
sp = 0;
CLR(vis, 0);
REP(i, n)
{
vis[a[i]] = 1;
if(sp)
{
if(s[sp - 1] > a[i])return 0;
else if(s[sp - 1] == a[i])sp--;
}
while(m < a[i])
{
if(!vis[m])s[sp++] = m, vis[m] = 1;
m++;
}
}
return 1;
}

int main()
{
//freopen("input.txt", "r", stdin);
//freopen("output.txt", "w", stdout);

while(RI(n), n)
{
while(RI(a[0]), a[0])
{
FF(i, 1, n)RI(a[i]);
puts(check() ? "Yes" : "No");
}
puts("");
}
return 0;
}