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| #include <bits/stdc++.h>
using namespace std;
const int N = 752, M=1e9+7;
int K, R, C, grid[N][N];
vector<map<int, int>> m;
vector<vector<int>> colorVector;
#ifdef NEW_SEGMENT_TREE
//https://usaco.guide/gold/PURS?lang=cpp
template<class T> struct Seg {
const T ID = 0; T comb(T grid, T b){ return (grid+b+M)%M; }
int n=0; vector<T> seg;
void init(int _n) { n = _n; seg.assign(2*n,ID); }
void pull(int p) { seg[p] = comb(seg[2*p],seg[2*p+1]); }
void upd(int p, T val) {
seg[p += n] += val; seg[p] %= M; for (p /= 2; p; p /= 2) pull(p); }
T query(int l, int r) {
T ra = ID, rb = ID;
for (l += n, r += n+1; l < r; l /= 2, r /= 2) {
if (l&1) ra = comb(ra,seg[l++]);
if (r&1) rb = comb(seg[--r],rb);
}
return comb(ra,rb);
}
};
#else
struct BIT {
vector<int> tree;
void init(int _n) { tree.resize(_n); }
void upd(int i, int x) {
while (i < tree.size()) {
tree[i] = (tree[i] + x);
//if (tree[i] < 0) tree[i] += M;
if (tree[i] > M) tree[i] -= M;
tree[i] = (tree[i] + M) % M;
i += (i & (-i));
}
}
long long query(int i) {
long long ans = 0;
while (i > 0) {
ans += tree[i];
//if (ans < 0) ans += M;
if (ans > M) ans -= M;
ans = (ans + M) % M;
i -= (i & (-i));
}
return ans;
}
};
#endif
long long ans[N];
int main() {
ifstream cin("hopscotch.in");
ofstream cout("hopscotch.out");
cin >> R >> C >> K;
colorVector.resize(K + 1);
m.resize(K + 1);
#ifdef NEW_SEGMENT_TREE
Seg<long long> colors[K+3],allColors;
#else
BIT colors[K + 3], allColors;
#endif
allColors.init(C+1);
for (int i = 1; i <= R; i++) {
for (int j = 1; j <= C; j++) {
int c;
cin >> c;
c--;
grid[i][j] = c;
colorVector[c].push_back(j);
}
}
for(int i = 0; i < colorVector.size(); i++) {
sort(colorVector[i].begin(), colorVector[i].end());
for (auto j : colorVector[i]) {
if (! m[i][j]) m[i][j] = m[i].size() + 1;
}
}
for (int i = 0; i < m.size(); i++)
colors[i].init(m[i].size()+2);
allColors.upd(1,1);
colors[grid[1][1]].upd(m[grid[1][1]][1],1);
for(int i=2; i<=R; i++){
for(int j=C; j>=2; j--){
int x = grid[i][j];
#ifdef NEW_SEGMENT_TREE
ans[j] = allColors.query(1,j-1) - colors[x].query(1, m[x][j]-1) + M;
#else
ans[j] = allColors.query(j-1) - colors[x].query(m[x][j]-1) + M;
#endif
ans[j] %= M;
allColors.upd(j, ans[j]);
colors[x].upd(m[x][j], ans[j]);
}
}
cout << ans[C];
}
|