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#include <algorithm>
#include <vector>
#include <iostream>
#include "poszukiwania.h"
#include "message.h"

void fillKMPTable(std::vector<int> &KMPTable) {
    long long signalLength = SignalLength();
    KMPTable.resize(size_t(signalLength + 1));
    KMPTable[0] = 0, KMPTable[1] = 1;
    long long signalFrontIndex = 1;
    for (long long signalBackIndex = 2; signalBackIndex < signalLength + 1;) {
        if (SignalAt(signalFrontIndex) == SignalAt(signalBackIndex)) {
            KMPTable[size_t(signalBackIndex)] = int(++signalFrontIndex);
            ++signalBackIndex;
        } else if (signalFrontIndex > 1) {
            signalFrontIndex = KMPTable[size_t(signalFrontIndex - 1)];
        } else {
            KMPTable[size_t(signalBackIndex)] = 1;
            signalFrontIndex = 1; ++signalBackIndex;
        }
    }
}

long long findMatchesKMP(long long from, long long to) {
    if (from >= to) {
        return 0;
    }
    std::vector<int> KMPTable;
    fillKMPTable(KMPTable);
    long long matchesFound = 0;
    for (long long wordIndex = from, patternIndex = 1; wordIndex - patternIndex + 1 < to;) {
        if (SeqAt(wordIndex) == SignalAt(patternIndex)) {
            ++wordIndex, ++patternIndex;
        } else if (patternIndex > 1) {
            patternIndex = KMPTable[size_t(patternIndex)];
        } else {
            patternIndex = 1, ++wordIndex;
        }
        if (patternIndex == SignalLength() + 1) {
            ++matchesFound;
            patternIndex = KMPTable[size_t(patternIndex - 1)];
        }
    }
    return matchesFound;
}

// heuristic

enum HashType {
    SUM_HASH = 0,
    DEC_HASH = 1,
    INC_HASH = 2,
};

void initHeuristics(long long from, long long (&patternHashes)[3], long long(&wordHashes)[3]) {
    patternHashes[0] = patternHashes[1] = patternHashes[2] =
        wordHashes[0] = wordHashes[1] = wordHashes[2] = 0;
    long long signalLen = SignalLength();
    long long currentSignal = 0;
    long long currentSeq = 0;
    for (int i = 1; i <= signalLen; ++i) {
        currentSignal = SignalAt(i);
        currentSeq = SeqAt(from + i - 1);
        patternHashes[SUM_HASH] += currentSignal;
        wordHashes[SUM_HASH] += currentSeq;
        patternHashes[DEC_HASH] += patternHashes[SUM_HASH];
        wordHashes[DEC_HASH] += wordHashes[SUM_HASH];
        patternHashes[INC_HASH] += i * currentSignal;
        wordHashes[INC_HASH] += i * currentSeq;
    }
}

void updateHashes(long long dropElem, long long(&wordHashes)[3]) {
    long long signalLength = SignalLength();
    long long dropSeq = SeqAt(dropElem);
    long long addSeq = SeqAt(dropElem + signalLength);
    wordHashes[INC_HASH] -= wordHashes[SUM_HASH];
    wordHashes[INC_HASH] += signalLength * addSeq;
    wordHashes[SUM_HASH] -= dropSeq;
    wordHashes[SUM_HASH] += addSeq;
    wordHashes[DEC_HASH] += wordHashes[SUM_HASH];
    wordHashes[DEC_HASH] -= signalLength * dropSeq;
}

bool hashesAreEqual(long long(&patternHashes)[3], long long(&wordHashes)[3]) {
    return patternHashes[0] == wordHashes[0] &&
        patternHashes[1] == wordHashes[1] &&
        patternHashes[2] == wordHashes[2];
}

long long findMatchesHeuristic(long long from, long long to) {
    if (from >= to) {
        return 0;
    }
    long long patternHashes[3], wordHashes[3];
    initHeuristics(from, patternHashes, wordHashes);
    long long matchesFound = 0;
    for (long long i = from; i < to - 1; ++i) {
        if (hashesAreEqual(patternHashes, wordHashes)) {
            ++matchesFound;
        }
        updateHashes(i, wordHashes);
    }
    if (hashesAreEqual(patternHashes, wordHashes)) {
        ++matchesFound;
    }
    return matchesFound;
}

int main() {
    long long nodeId = MyNodeId();
    int numberOfNodes = NumberOfNodes();
    long long potentialMatchPositions = SeqLength() - SignalLength() + 1;
    long long nodeCount = (potentialMatchPositions + numberOfNodes - 1) / numberOfNodes;
    long long nodeStart = nodeId * nodeCount + 1;
    long long nodeEnd = std::min(nodeStart + nodeCount, potentialMatchPositions + 1);

    long long matchesFound = 0;
    if (SignalLength() <= 2 * 10000000) {
        matchesFound = findMatchesKMP(nodeStart, nodeEnd);
    } else {
        matchesFound = findMatchesHeuristic(nodeStart, nodeEnd);
    }
    if (nodeId > 0) {
        PutLL(0, matchesFound);
        Send(0);
    } else {
        for (int i = 0; i < numberOfNodes - 1; ++i) {
            int inst = Receive(-1);
            matchesFound += GetLL(inst);
        }
        std::cout << matchesFound;
    }
}