Noip 2005 过河

#include <algorithm>#include <iostream>#include <cstring>#include <cstdio>using namespace std;#define debug(x) cerr << #x << "=" << x << endl;const int MAXN = 10000000 + 10;const int INF = 1<<30 - 1;int l,s,cnt,t,m,a[MAXN],ans,dp[MAXN],b[MAXN]; int main() {    cin >> l;    cin >> s >> t >> m;    for(int i=1; i<=m; i++)         cin >> a[i];     if(s == t) {        int tot = 0;        for(int i=1; i<=m; i++)             if(a[i] % s == 0)                 tot++;        cout << tot << endl;        return 0;    }    sort(a+1,a+m+1);    for(int i=1; i<=m; i++) {        int dis = a[i] - a[i-1];        a[i] = a[i-1] + dis%100;        b[a[i]] = 1;    }    l = (l - a[m]) % 100 + a[m];    for(int i=1;i<=m;i++)        b[a[i]]=1;    memset(dp,0x3f,sizeof(dp));    dp[0] = 0;    for(int i=s; i<=l+t; i++)         for(int k=s; k<=t; k++)             if(i - k >= 0)                 dp[i] = min(dp[i], dp[i-k] + b[i]);    int ans = INF;    for(int i=l; i<=l+t; i++)         ans = min(ans, dp[i]);    cout << ans;    return 0;}