题解 挖掘机
首先贪心的思路很好想
然后发现如果有 \(>k\) 的空缺，贪心的部分会断掉
所以可以分成几块，二分出询问的区间包含了哪些段
但是只包含了一部分的不好处理
于是换个思路，考虑倍增优化贪心覆盖
考场上因为倍增的时候跳出边界了没跳出来炸掉了
考完拿拍造了几百组数据面向数据调试过了
Code:
#include <bits/stdc++.h>
using namespace std;
#define INF 0x3f3f3f3f
#define N 100010
int h, w, k, q;
char s[N];
bool mp[13][N];
namespace force{
void solve() {
for (int i=1,d,l,r; i<=q; ++i) {
int ans=0;
scanf("%d%d%d", &d, &l, &r);
for (int t=1; t<=d; ++t) {
int lst=-1;
for (int j=l; j<=r; ++j) if (mp[t][j]) {
if (lst==-1 || j>lst+k-1) ++ans, lst=j;
}
}
printf("%d\n", ans);
}
exit(0);
}
}
namespace task1{
int pre[13][N], suf[13][N], siz[13], sum[13][N];
struct range{
int l, r, val;
range(){}
range(int a, int b) {l=a; r=b;}
inline void build(int a, int b, int c) {l=a; r=b; val=c;}
}rg[13][N];
inline bool cmp1(range a, range b) {return a.l<b.l;}
inline bool cmp2(range a, range b) {return a.r<b.r;}
void solve() {
for (int i=1; i<=h; ++i) {
int lst=-1, beg;
for (int j=1; j<=w; ++j) if (mp[i][j]) {
if (lst==-1) lst=j, beg=j;
else if (j>lst+k-1) {rg[i][++siz[i]].build(beg, lst, (lst-beg)/k+1); beg=lst=j;}
else lst=j;
}
if (lst!=-1) rg[i][++siz[i]].build(beg, lst, (lst-beg)/k+1);
rg[i][++siz[i]].build(INF, INF, 0);
for (int j=1; j<=siz[i]+1; ++j) sum[i][j]=sum[i][j-1]+rg[i][j].val;
// if (i==4) {cout<<"rg: "; for (int j=1; j<=siz[i]; ++j) cout<<rg[i][j].l<<','<<rg[i][j].r<<','<<rg[i][j].val<<' '; cout<<endl;}
lst=-1;
for (int j=1; j<=w; ++j) {
if (mp[i][j]) lst=j;
pre[i][j]=lst;
}
lst=-1;
for (int j=w; j; --j) {
if (mp[i][j]) lst=j;
suf[i][j]=lst;
}
}
for (int i=1,d,l,r; i<=q; ++i) {
// cout<<"i: "<<i<<endl;
int ans=0;
scanf("%d%d%d", &d, &l, &r);
// cout<<"lr: "<<l<<' '<<r<<endl;
for (int t=1; t<=d; ++t) {
// cout<<"t: "<<t<<endl;
int pos1=lower_bound(rg[t]+1, rg[t]+siz[t]+1, range(l, -1), cmp1)-rg[t];
int pos2=lower_bound(rg[t]+1, rg[t]+siz[t]+1, range(-1, r), cmp2)-rg[t];
if ((~suf[t][l]&&~pre[t][r]) && (suf[t][l]<=r&&pre[t][r]>=l)) {
if (pos1==pos2+1) {
ans+=(pre[t][r]-suf[t][l])/k+1;
}
else {
if (pos1>1 && rg[t][pos1-1].r>=suf[t][l] && rg[t][pos1-1].r<=pre[t][r]) {
ans+=(rg[t][pos1-1].r-suf[t][l])/k+1;
// if (t==9) cout<<"r1: "<<(rg[t][pos1-1].r-l)/k+1<<endl;
}
if (rg[t][pos2].l<=pre[t][r]) {
ans+=(pre[t][r]-rg[t][pos2].l)/k+1;
// if (t==9) cout<<"r2: "<<(r-rg[t][pos2].l)/k+1<<endl;
}
ans+=sum[t][pos2-1]-sum[t][pos1-1];
}
}
// if (t==4) cout<<"pos: "<<pos1<<' '<<pos2<<endl;
// cout<<"ans: "<<ans<<endl;
// cout<<"add: "<<sum[t][pos2-1]-sum[t][pos1-1]<<endl;
}
printf("%d\n", ans);
}
exit(0);
}
}
namespace task2{
int pre[13][N], suf[13][N], siz[13], sum[13][N];
int dp[13][30][N];
inline int dep(int j) {return w-j+1;}
void solve() {
for (int i=1,lst; i<=h; ++i) {
lst=0;
for (int j=1; j<=w; ++j) {
if (mp[i][j]) lst=j;
pre[i][j]=lst;
}
lst=w+1;
suf[i][w+1]=w+1;
for (int j=w; j; --j) {
if (mp[i][j]) lst=j;
suf[i][j]=lst;
}
for (int j=1; j<=w; ++j) {
dp[i][0][j]=suf[i][j]+k-1;
cout<<"dp[0]: "<<j<<' '<<dp[i][0][j]<<endl;
}
for (int j=w; j; --j) {
for (int s=1; s<25; ++s)
if (dep(j)>(1<<s)) {
if (dp[i][s-1][j]<=w) {
dp[i][s][j]=suf[i][dp[i][s-1][j]];
// cout<<"suf: "<< suf[i][dp[i][s-1][j]] <<endl;
if (suf[i][dp[i][s-1][j]]<=w) {
dp[i][s][j]=dp[i][s-1][ suf[i][dp[i][s-1][j]] ];
cout<<"dp: "<<dp[i][s][j]<<endl;
cout<<"from: "<<i<<' '<<s<<' '<<j<<endl;
cout<<"get: "<<i<<' '<<s-1<<' '<<suf[i][dp[i][s-1][j]]<<endl;
}
}
else dp[i][s][j]=w;
}
else dp[i][s][j]=w;
}
}
for (int i=1,d,l,r; i<=q; ++i) {
// cout<<"i: "<<i<<endl;
int ans=0;
scanf("%d%d%d", &d, &l, &r);
// cout<<"lr: "<<l<<' '<<r<<endl;
for (int t=1; t<=d; ++t) {
// cout<<"t: "<<t<<endl;
int now=suf[t][l], ed=pre[t][r];
cout<<"now: "<<now<<endl;
for (int j=25; ~j; --j)
if (now<=ed && dp[t][j][now] && dp[t][j][now]<=ed) {
ans+=(1<<j);
now=suf[t][dp[t][j][now]];
cout<<"jump: "<<now<<' '<<j<<' '<<suf[t][dp[t][j][now]]<<endl;
}
}
printf("%d\n", ans);
}
exit(0);
}
}
namespace task{
int pre[13][N], suf[13][N], siz[13], sum[13][N];
int dp[13][18][N], dep[13][N];
void solve() {
for (int i=1,lst; i<=h; ++i) {
lst=0;
for (int j=1; j<=w; ++j) {
if (mp[i][j]) lst=j;
pre[i][j]=lst;
}
lst=w+1;
suf[i][w+1]=w+1;
for (int j=w; j; --j) {
if (mp[i][j]) lst=j;
suf[i][j]=lst;
}
for (int j=w; j; --j) {
if (j+k-1>=w) dep[i][j]=1;
else if (!mp[i][j]) dep[i][j]=dep[i][suf[i][j]];
else dep[i][j]=dep[i][suf[i][j+k]]+1;
// cout<<"dep["<<j<<"]: "<<dep[i][j]<<endl;
}
for (int j=1; j<=w; ++j) {
dp[i][0][j]=min(suf[i][j]+k, w+2);
// cout<<"dp[0]: "<<j<<' '<<dp[i][0][j]<<endl;
}
for (int j=w; j; --j) {
for (int s=1; s<=17; ++s)
if (dep[i][j]>=(1<<s)) {
dp[i][s][j]=dp[i][s-1][ suf[i][dp[i][s-1][j]] ];
}
else dp[i][s][j]=w+2;
}
}
for (int i=1,d,l,r; i<=q; ++i) {
// cout<<"i: "<<i<<endl;
int ans=0;
scanf("%d%d%d", &d, &l, &r);
// cout<<"lr: "<<l<<' '<<r<<endl;
for (int t=1; t<=d; ++t) {
// cout<<"t: "<<t<<endl;
int now=suf[t][l], ed=pre[t][r]+1;
// cout<<"now: "<<now<<' '<<ed<<endl;
for (int j=17; ~j; --j) {
// cout<<"j: "<<j<<' '<<now<<' '<<dp[t][j][now]<<endl;
if (now<ed && dp[t][j][now]<=ed) {
ans+=(1<<j);
// cout<<"jump: "<<now<<' '<<j<<' '<<suf[t][dp[t][j][now]]<<endl;
now=suf[t][dp[t][j][now]];
}
}
if (now<ed) ++ans;
}
printf("%d\n", ans);
}
exit(0);
}
}
signed main()
{
freopen("blueshit.in", "r", stdin);
freopen("blueshit.out", "w", stdout);
scanf("%d%d%d%d", &h, &w, &k, &q);
for (int i=1; i<=h; ++i) {
scanf("%s", s+1);
for (int j=1; j<=w; ++j) mp[i][j]=(s[j]=='X')?1:0;
}
// if (w<=1000) force::solve();
// else task1::solve();
task::solve();
return 0;
}
